I. Introduction

Judge Learned Hand wrote that it is “a totally different thing to search a man’s pockets and use against him what they contain, from ransacking his house for everything which may incriminate him.”[1] Reflecting on this statement eighty-eight years later in Riley v. California, the U.S. Supreme Court added this caveat: “If his pockets contain a cell phone, however, that is no longer true.”[2] Due to the prevalence of digital storage, and the ease with which people can transport their digital lives, without restrictions on digital searches, the government constantly risks the general rummaging Judge Hand warned against, and which the Constitution seeks to prevent.[3]

The Fourth Amendment protects from unreasonable searches and seizures, but both state and federal courts struggle to define “unreasonable” within the digital context.[4] The nature of digital searches creates the difficulty. Reasonable searches occur pursuant to a judicially issued warrant or within specific exceptions to the warrant requirement with the intent of limiting the searching official’s discretion.[5] But warrants and exceptions only suffice to limit physical intrusions into privacy; the primary concern of unreasonableness begins once the intangible search begins.[6]

Academics and commentators wrangle over whose approach best balances law enforcement needs against individual privacy concerns. The Supreme Court has weighed in only in limited instances,[7] and until the Court renders an illuminating opinion in the vein of Riley,[8] those attempting to navigate Fourth Amendment waters travel perilously close to a rocky shoreline. For now, courts must pilot the shoals with whatever tools they find on hand.[9]

One such tool—and the subject of this Comment—is Professor Orin Kerr’s proposed use restriction on “ongoing seizures,” as suggested in his 2015 article, Executing Warrants for Digital Evidence: The Case for Use Restrictions on Nonresponsive Data.[10] Under Kerr’s approach, any use of digital data unresponsive to a search warrant qualifies as an unreasonable second seizure.[11] In the years since his proposal, courts have not rushed to apply Kerr’s “ongoing seizure” restriction, but neither have courts entirely ignored it—with one state adopting it wholesale.[12] So, too, have scholars considered the merits of Kerr’s “ongoing seizure” approach with mixed reception.[13] Perhaps a different approach offers a better solution.[14]

This Comment proceeds as follows: Part II charts the difficulties embedded within digital data searches and explains how Kerr’s “ongoing seizure” limitation proposes to circumvent those difficulties; Part III examines courts’ uses of the Kerr approach; Part IV discusses alternative approaches used by courts and suggested by the academic community; and finally, Part V advocates for the use of evidentiary firewalls.

II. Background

Harold Krent’s 1995 proposal of use restrictions arose from a concern that law enforcement would retain physical evidence for subsequent use following a seizure.[15] The idea lay dormant until 2011, when Kerr suggested applying use restrictions to data seizures in criminal prosecutions.[16] Use restrictions have expanded beyond the physical intrusions imagined by Krent and now seek a place within the digital world.[17]

This Part of the Comment first introduces the trouble created by digital data and how scholars and the Supreme Court have sought to navigate it in the past. Next, using United States v. Morton as an example, it provides a real-world instance where law enforcement’s use of digital search resulted in the discovery of nonresponsive material, implicating the Fourth Amendment privacy concerns at the center of use restrictions. Lastly, it describes how Professor Kerr’s use restriction on “ongoing seizures” proposes to limit law enforcement’s intrusion into individual digital privacy.

A. Unique Fourth Amendment Challenges Presented by Digital Searches

Digital searches present unique problems not present in the physical world and need novel restrictions to avoid a government’s trend toward tyranny.[18] The U.S. Supreme Court confronted this novelty for the first time in Riley.[19] The Court combined two cases in which cell phones seized during searches incident to the arrests yielded information law enforcement used to facilitate additional charges or subsequent searches.[20] Both trial courts refused to suppress the evidence that led to the eventual convictions.[21] The Supreme Court acknowledged the privacy concerns implicated by the modern cell phone’s “immense storage capacity.”[22] In its response to Judge Hand’s ruminations on the difference between a man’s pocket and his house, the Court noted that a “phone not only contains in digital form many sensitive records previously found in the home; it also contains a broad array of private information never found in a home in any form—unless the phone is.”[23] In light of the privacy risk cell phones pose, the Court required law enforcement to obtain a search warrant before searching a cell phone, even when seized incident to arrest.[24]

Digital storage has expanded in the years since Riley. A one-terabyte thumb drive holds the data equivalent of 65 million printed pages, 100 million e-mails, 16 million images, and 675 million text messages.[25] The Second Circuit noted that it is possible to purchase a storage device containing the equivalent of “16 billion thick books.”[26] However, binary data means nothing to the human mind, and a computer’s organizational structures do not reflect the tidy images evoked by the interface software’s use of files and folders.[27] Digital evidence often cannot be fully known until it is opened.[28]

Recognizing the complications in finding a metaphorical needle in a digital haystack, Congress authorized courts to warrant overseizure.[29] A warrant first authorizes a search of the physical location and the seizure of the digital storage devices described in the application and supporting affidavits.[30] Following the seizure, in an attempt to conform with the Fourth Amendment’s particularity requirement, law enforcement renders data into a perfect electronic copy that a forensic examiner later analyzes to separate data responsive to the warrant from unresponsive data.[31] But courts often permit law enforcement to search the data anywhere that evidence relevant to the inquiry might be found, if only to rule out data corruption or virus intrusion.[32] Courts have split on when—and even if—a digital search ever becomes unreasonable for subjective searches beyond a warrant’s scope, leading to encounters with nonresponsive data.[33] In a typical physical search, nonresponsive evidence in plain view falls within an exception to the Fourth Amendment.[34] But whether the plain view exception should apply in the digital context remains unclear.[35] Exposure to nonresponsive data raises the reasonableness question that Kerr and other scholars have attempted to answer.

B. The Fifth Circuit Circumvented Unreasonableness in United States v. Morton[36]

The digital and highly sensitive nature of child pornography in the modern world can potentially skew jurisprudence in favor of the government.[37] Gray-area digital searches force courts to choose between letting potential child predators go free or treading on individual privacy interests. The Fifth Circuit confronted this issue in United States v. Morton.[38]

Morton consented to a search of his van after being pulled over for speeding, and Texas Department of Public Safety (DPS) Troopers found ecstasy, marijuana, and a glass pipe within.[39] More concerning to the troopers, Morton’s van contained “children’s school supplies, a lollipop, 14 sex toys, and 100 pairs of women’s underwear.”[40] They arrested Morton for drug possession.[41]

In a warrant application to search three cell phones found in Morton’s van, the troopers only described evidence of Morton’s criminal drug activity; they did not mention suspicion of child predation or exploitation.[42] The subsequent search uncovered sexually explicit images of children.[43] A second warrant to search for child pornography, based on probable cause arising from the first search, produced “19,270 images of sexually exploited minors.”[44] Morton’s motion to suppress the images failed; he pled guilty to child pornography charges conditional upon appeal and the court sentenced him to nine years in prison.[45]

On appeal to the Fifth Circuit, a three-judge panel held that because the first warrant lacked sufficient probable cause to search the phones for drug-related evidence, any further evidence originating from that search was “fruit of the poisonous tree”; thus, the trial court erred by not suppressing it.[46] On a rehearing en banc, the full Fifth Circuit vacated the panel opinion and affirmed the trial court’s decision, basing its holding on the officers’ good faith reliance on the magistrate’s warrant.[47]

A five-judge concurrence recognized the echoes of Riley. The concurrence expressed concern that even “with such a meager showing, officers would gain unfettered access to all of ‘the privacies of life.’”[48] The concurring judges asked whether Kerr’s use restriction might create the right solution to a situation like Morton’s, noting that one state had already applied Kerr’s approach.[49] The concurrence concluded by observing that the Supreme Court should—and likely would—make a Riley-like adjustment to Fourth Amendment jurisprudence in the future.[50] Unfortunately, the Court rejected Morton’s petition for a writ of certiorari, so it does not appear that a “Riley moment” will soon arrive.[51]

C. Orin Kerr’s “Ongoing Seizure” Use Restriction

Given the right circumstances, Kerr believes the Supreme Court will reevaluate an old paradigm and, considering new facts, “adopt a new rule to restore the equilibrium struck by the old rule in the old factual environment.”[52] The plain view exception no longer suffices—it produces results too close to general rummaging.[53] However, eliminating the plain view exception in digital searches fails to solve the problem. The exception applies to seizing evidence in plain view; and because law enforcement has already seized digital evidence when viewed, plain view can no longer apply.[54] The doctrinal shift, Kerr argues, should come from use restrictions imposed on the data that is nonresponsive to the warrant during a comprehensive search following an overseizure.[55]

Kerr suggests that the use of nonresponsive files “violates the Fourth Amendment in a two-stage computer search because it renders the ongoing seizure of the nonresponsive files constitutionally unreasonable.”[56] He points to United States v. Jacobsen, in which law enforcement opened a lawfully seized package containing cocaine and destroyed a small portion of the cocaine to test it.[57] While the Supreme Court held this search reasonable under a balancing test that weighed the “nature and quality of the intrusion” against the important “governmental interests alleged to justify the intrusion,” the Court indicated that a secondary seizure is never presumptively reasonable.[58] Building on this, Kerr argues that courts should consider the subsequent use of lawfully seized nonresponsive digital data presumptively unreasonable.[59] Subsequent use transforms the “nature and quality” of the seizure into the prohibited general warrant and eliminates the Fourth Amendment’s particularity requirement.[60] Further, subsequent use offends the proportionality principle established in Terry v. Ohio for failing to remain “reasonably related in scope to the circumstances which justified the interference in the first place.”[61]

An “ongoing seizure” analysis asks whether further use satisfies Terry.[62] Kerr provides a list of situations in which this application results in an unreasonable secondary seizure. First, utilizing nonresponsive data no differently from data cited in the warrant violates the Terry requirement.[63] Second, additional warrants based on probable cause created by nonresponsive data create a similar violation, rendering the difference between first and subsequent warrants into nothing more than paperwork obstacles.[64] And third, disclosing nonresponsive data to the public renders it unreasonable—especially when the information might reveal the individual’s “prurient interests or personal foibles.”[65]

How might the Fifth Circuit have ruled in Morton if the court had considered Kerr’s “ongoing seizure” use restriction beyond a mention in the concurrence?[66] First, in line with Riley, troopers seized Morton’s cell phones pursuant to a search incident to arrest and did not begin a search until after obtaining a warrant.[67] At this point, the facts do not collide with Kerr’s use restriction. However, because the troopers obtained a search warrant seeking only data indicative of drug trafficking, exposure to any data nonresponsive to that warrant would collide.[68] The moment the troopers encountered images of child exploitation, Kerr’s “ongoing seizure” restriction would be triggered, making any subsequent use of that data unreasonable under the Fourth Amendment.[69]

Had an “ongoing seizure” restriction existed at the time, the troopers would not have had recourse to seek a second warrant.[70] And even if a magistrate had issued a second warrant, any successive court reviewing the constitutionality of the second warrant would have to conclude that it violated the Fourth Amendment’s prohibition against unreasonable searches and seizures.[71]

In Morton, the en banc Fifth Circuit upheld the trial court’s denial of Morton’s motion to suppress on the basis that the troopers—in their first search of Morton’s phones—acted in good faith reliance on the warrant.[72] But with Kerr’s “ongoing seizure” use restriction in place, when determining good faith, the Fifth Circuit would have found the second warrant a violation of the Fourth Amendment and prevented officers from converting a “traffic stop that produced evidence of a marginal offense” into “an excuse to gain unfettered access to a device saturated with personal, private information.”[73] Morton might still have found himself convicted, but only of minor drug possession, not for possession of child pornography.

As discussed below, the one court to have adopted Kerr’s approach did so with mixed results.[74] Kerr even expressed regret at one result, which allowed a father who had allegedly shaken his infant to death to go free.[75]

III. Among Courts, Kerr’s Use Restriction on “Ongoing Seizures” has Received Limited Welcome.

Kerr’s use restriction has seen little adoption. At the time of Kerr’s publication, the Second Circuit appeared to adopt an “ongoing seizure” approach—the only federal court to do so—but it backtracked. Further, organizations dedicated to protecting individual liberties and digital freedom have petitioned the federal courts to consider Kerr-style restrictions. They have only met silence. While one state court has adopted a version of this use restriction, most have not considered it, and those that have, have either ignored or rejected the approach.

This Part reviews the application of Kerr’s use restriction—if any—within the federal and state court systems.

A. Federal Courts

Though some judges have taken note of Kerr’s “ongoing seizure” approach, federal courts have generally ignored it. In a case built on the subsequent search of previously seized data, a three-judge panel from the Second Circuit applied what Kerr described as “a particularly strong version of the ongoing seizure approach.”[76] However, any potential adoption remained short-lived; shortly before Kerr’s article was published, the Second Circuit granted a rehearing en banc.[77] As with the Fifth Circuit in Morton, the Second Circuit decided the appeal on the good faith exception and declined to evaluate the merits of the Fourth Amendment challenge.[78] Regarding the application of the “ongoing seizure” approach, the en banc opinion found “no scholarly consensus on the complicated questions implicated in this case” and advised caution as “the most appropriate approach.”[79] The Second Circuit has yet to adopt Kerr’s approach.

District courts have declined to engage with the “ongoing seizure” use restriction. A Nevada district court mentioned Kerr’s approach as a “workable solution” for “appropriately narrow warrants” and the subsequent use of data; however, it did not apply the solution as the warrant under its consideration proved “fatally overbroad.”[80] A South Dakota district court magistrate judge referenced Kerr’s “ongoing seizure” use restriction in recommending that “the plain view exception to the warrant requirement be held not applicable in searches of digital evidence.”[81] However, when the district court judge modified the opinion before adoption, that judge omitted the Kerr reference.[82]

Similarly, federal appellate courts have remained mute when criminal appellants invoke Kerr’s use restriction. When petitioned to weigh in on the issue of digital searches and to issue a “Riley moment,” as Kerr prompted, the Supreme Court remained silent, denying certiorari on the matter.[83] As amici, the Electronic Frontier Foundation (EFF) and the American Civil Liberties Union (ACLU) asked the Ninth Circuit to block evidence of child pornography found on a cellphone pursuant to a search conducted under a Foreign Intelligence Surveillance Act (FISA) warrant because it did not pertain to foreign intelligence.[84] The Ninth Circuit thanked the EFF and the ACLU “for their thought-provoking briefing,” admitting the situation came close to “the exact abuses against which the Fourth Amendment was designed to protect,” but found no error.[85]

At the time of this Comment’s writing, no federal court has adopted Kerr’s “ongoing seizure” use restriction. However, two years before Kerr’s article’s publication, the Ninth Circuit arrived at a close facsimile, holding that “[t]he government’s seizure of items beyond the terms of [a digital search] warrant violated the Fourth Amendment.”[86] The five-judge concurrence in Morton remains the strongest mention of Kerr’s approach to appear in a standing federal court opinion.[87]

B. State Courts

In 2018, Oregon adopted the “ongoing seizure” use restriction in State v. Mansor, heavily rooting its legal theory in Kerr’s scholarship.[88] There, police drafted a narrow warrant seeking Mansor’s internet search history for the day his infant son died.[89] Police later added Mansor’s e-mail to the list and provided FBI forensic analysts with an expanded list of search terms and a wider timeframe in which to search, all without obtaining an additional warrant.[90] The analysts further added their own search terms.[91] The subsequent report detailed a comprehensive history of Mansor’s entire digital life, going back six years before the infant’s birth.[92] The trial court denied Mansor’s motion to suppress on the basis that the digital data fell within the plain view exception; a jury convicted him on all charged counts.[93]

The Oregon Supreme Court rejected the holdings of both lower courts.[94] Instead, the state high court relied on Kerr’s proposal to hold that data nonresponsive to a warrant should be suppressed.[95] Kerr applauded the state’s adoption—while simultaneously lamenting that a poorly drafted warrant vacated a child abuser’s conviction for murder. But, he added this caveat: because the court decided Mansor under the Oregon Constitution’s search and seizure provision, “the decision is interesting and relevant more by way of illustration than precedent.”[96]

But even the Mansor holding has come under some attack when applied without nuance. The Oregon Court of Appeals questioned whether data obtained lawfully—but which fell outside the warrant’s scope—fell within Mansor’s prohibitions.[97] Post-Mansor cases had not provided an answer, so the court resorted to reading tea leaves.[98] It reasoned that, in light of Mansor, the Oregon Supreme Court would likely prohibit any use of the data in question.[99] As a result, law enforcement could not use the data obtained during a lawful search that fell outside the warrant.[100] Nor could it use that data to develop probable cause to obtain a second warrant or to further additional lines of investigation.[101] The concurrence argues that the Mansor line of cases requires law enforcement to “turn a blind eye to criminal activity that lawfully comes to their attention” and hopes the Oregon Supreme Court will clarify its prohibitions on use.[102]

No other states have adopted Oregon’s approach. Following Mansor, the Indiana Court of Appeals observed that an officer’s failure to abide by a warrant’s date restriction rendered digital evidence outside that warrant’s scope inadmissible.[103] However, the nonresponsive evidence did not factor in either of the trial court’s rulings in that case, and played no part in the appellate court’s holding.[104] In another case, the Supreme Court of Wisconsin registered no reaction to an amicus filing by the ACLU suggesting the court adopt Mansor’s application of Kerr’s use restriction.[105] Similarly, the Superior Court of Pennsylvania, Middle District, remained silent to the suggestion it should apply a Mansor-style use restriction to any evidence exceeding a search warrant.[106] In a separate case, the Supreme Court of Pennsylvania declared a warrant void for lack of probable cause without engaging with the use restrictions suggested in an amicus brief.[107]

While Oregon stands alone in adopting Kerr’s “ongoing search” use restriction, nothing indicates whether this results from a lack of the right facts or from a reluctance of the courts to implement such a restrictive approach.

IV. Legal Commentators Offer Competitive Approaches to Protect Privacy Interests from Intrusive Digital Searches

Legal commentators have offered no more than a lukewarm reception of Kerr’s use restriction against “ongoing seizures.” Some have offered competitive solutions, while others have addressed specific flaws in the approach. Consensus remains elusive. This Part first describes the issues arising from post hoc review. It next addresses how ex ante restrictions potentially avoid pitfalls presented by Kerr’s post hoc approach. It concludes with an analysis of how Kerr’s “ongoing seizure” use restriction creates potential conflicts with governmental obligations required under Brady v. Maryland.

A. Post Hoc Problems

The post hoc nature of Kerr’s use restriction presents prosecutors and courts with difficult choices. Because Kerr’s approach limits the use of data found outside the scope of warrants, instituting it provides an incentive to broadly expand the scope of warrant applications.[108] Further, law enforcement can freely use evidence of other crimes discovered within the data responsive to the warrant.[109] Courts then find themselves in a position of evaluating the totality of circumstances to determine the reasonableness of the search,[110] or in the case of Mansor, limiting the construction of the warrant post hoc.[111]

But even in Mansor, had law enforcement broadened the initial warrant or properly sought a second one upon creation of new probable cause, that court would not have had occasion to institute Kerr-style use restrictions.[112] Ultimately, if law enforcement searches digital evidence within the reasonable limitations a warrant provides, any evidence of additional crimes appearing within that scope requires additional warranted permission from a magistrate to remain within the Fourth Amendment—a practice used by the officers in Morton.[113]

Relying on post hoc review can create uncertainty for law enforcement and the courts.[114] As Kerr noted in his response to Mansor, the investigating officers probably did not expect the court to construe their warrant as narrowly as it did.[115] Additionally, as seen in Morton, courts often deal with digital searches in the context of child pornography cases.[116] Because courts exhibit a reluctance to release those convicted of creation or possession of child pornography, caselaw in this area favors the government.[117] Encountering factual situations starkly different from the child pornography context might leave courts looking for other approaches that more favorably solve the digital search problem.

B. Ex Ante Restrictions

Noting the difficulties arising out of the post hoc nature of Kerr’s approach, ex ante restrictions seek to eliminate constitutional violations before they happen. FISA courts use a procedure arising from Title III wiretaps called minimization.[118] Minimization “is any set of procedures ‘reasonably designed in light of the purpose and technique’ of information collection ‘to minimize the acquisition and retention, and prohibit the dissemination,’ of information whose collection is not authorized.”[119] Following the model of FISA courts, magistrates would require the government to propose rules to the court governing the collection and sifting of digital data.[120] Magistrates and the government work hand-in-hand to tailor governmental needs specific to each investigation while balancing individual privacy issues.[121] Following seizure, FISA courts insulate data by utilizing separate analysts to sift for data responsive to the warrant without ever exposing the evidence to investigators directly responsible for the case.[122] Upon finding evidence of additional crimes, investigators can always return to the magistrate to adjust the warrant’s scope.[123]

Additionally, this approach removes the unfortunate side effects of Kerr’s post hoc approach. First, delineating clear rules provides law enforcement with predictability and prevents relying on guesswork as to what each court regards as appropriate.[124] Second, the plethora of post hoc appeals challenging digital searches arising in child pornography cases create a disproportionate body of caselaw relying on unsympathetic defendants.[125] Third, the cooperative nature of minimization techniques between law enforcement and the magistrate eliminates over-reliance on the good-faith exception to circumvent constitutional violations.[126] Minimization provides the benefit of utilizing the FISA format, already familiar within the court system, applied via ex ante restrictions already used by magistrates.[127]

C. Brady Concerns Arising from Kerr’s “Ongoing Seizure” Use Restriction

Regardless of ex ante or post hoc restrictions, the “ongoing seizure” approach creates a conflict arising from the government’s Brady obligations.[128] This “Digital Disclosure Trilemma,” as one commentator describes it, creates a paradox of obligations for the government.[129] First, under Brady, the government must disclose all exculpatory evidence within its possession—including evidence seized but outside the scope of the search warrant.[130] Second, in turning over evidence, the government must comply with a discovery statute restricting it from turning over “any property or material that constitutes child pornography.”[131] Without reviewing all the digital evidence within its possession, the government cannot satisfy its Brady obligations.[132] However, reviewing all the digital evidence exposes the government to nonresponsive data and risks falling afoul of Kerr’s “ongoing seizure” use restriction, eliminating the government’s ability to properly develop probable cause for additional crimes contained within the digital evidence.[133]

The Fourth Amendment remains the guiding star here, and though little agreement exists within the courts and between commentators, one throughline exists. The next Part discusses a solution: increased use of evidentiary firewalls.

V. Utilizing an Evidentiary Firewall Provides the Desired Fourth Amendment Safeguards

Creating an evidentiary firewall requirement will provide the simplest way to protect the Fourth Amendment right to individual privacy without substantially burdening the government in its effort to execute its mandate. This Part advocates building on similar formats that already exist within FISA, attorney-client, and government contexts. Building on existing formulas prevents courts and law enforcement from having to create a new system out of whole cloth. Additionally, it addresses how the development of computer-assisted searches will further reduce the need for human investigators to execute interactive data searches, helping solve potential Brady issues. It concludes by discussing how the use of an evidentiary firewall would have affected Morton.

A. Applying Already Existing Evidentiary Firewall Procedures to Digital Searches

The evidentiary firewall concept already exists within governmental protocols for occasions when law enforcement searches sensitive or privileged materials.[134] As discussed above, FISA courts apply similar measures to mass-collected data in the national security context.[135] Applying a similar insulating approach to criminal investigations following a Rule 41 overseizure prevents investigators from directly accessing nonresponsive data.[136]

The Department of Justice (DOJ) Justice Manual illustrates how this process works in the context of investigating an attorney.[137] First, law enforcement should write the warrant “to minimize the need to search and review privileged material to which no exception applies.”[138] Second, a privilege team consisting of non-investigatory agents or lawyers follows instructions “designed to minimize intrusion into privileged materials,” ensuring the team “does not disclose any information to the investigation/prosecution team unless and until so instructed by the attorney in charge of the privilege team.”[139]

Courts prefer three methods concerning privileged digital materials.[140] First, in camera review; second, the court can appoint a special master; and third, the court can use a filter team that establishes what the DOJ terms an “ethical wall” in privilege situations.[141] Of the three, filter teams perform the work quickest, though some courts express reluctance to use them.[142] Ultimately, as long as filter team procedures “adequately protect[] the defendants’ rights and no prejudice occur[s],” then courts have generally approved of their use.[143]

Utilizing an evidentiary firewall solves many of the problems encountered with Kerr’s “ongoing seizure” use restriction and the alternative solutions proposed by other commentators. First, the firewall provides insulation for the investigators—they will only ever see the evidence provided to them by a filter team.[144] This reduces the requirement for the circuit courts to construct broad rules based on the adherence of investigators to existing jurisprudence; instead, it reduces the review to whether law enforcement acted within the filter team protocols.[145] The Supreme Court should provide the review standard, removing the need for magistrates to apply ex ante restrictions. Kerr’s post hoc review preference would no longer rest on arbitrary magistrate decisions but review reasonableness in the context of the ultimate ex ante protocols—U.S. Supreme Court rulings.

Second, an evidentiary firewall approach alleviates the concern that jurisprudence in this area disproportionately originates in cases involving child pornography.[146] Review in these cases becomes fact specific and no longer broadly addresses the area of digital searches.[147] And third, because this approach puts the onus on investigators and the filter team to follow either judicial orders ex ante or Supreme Court holdings, it removes the need for appellate courts to rely on the good-faith exception to protect society from child predators.[148]

B. Utilizing Computer Algorithmic Binary Searches to Solve the Brady Problem

The continued development of technology in this sphere can assist filter teams on the non-investigatory side of the firewall. Similar to how courts view narcotics field tests and drug dog searches, applying the principle of binary searches to computer-assisted digital searches further provides a Fourth Amendment buffer.[149] The Supreme Court has held that evidence of criminal contraband does not fall within the scope of a “legitimate privacy interest.”[150] Because a binary test only reveals the presence or lack of contraband, any binary test conducted where an officer is lawfully present that reveals “no information other than [contraband] no individual has any right to possess does not violate the Fourth Amendment.”[151]

On the filtration side of the firewall, computer algorithms can mine the data and only reveal digital evidence comporting with the search warrant’s particularity requirements.[152] Additionally, law enforcement could opt to only search the data for elements of probable cause; once armed with probable cause, law enforcement could seek a warrant to observe the data.[153] Because the nature of these searches remains binary, no Fourth Amendment implications exist.[154]

Employed together, evidentiary firewalls and binary searches can effectively neutralize the Brady concerns illustrated above.[155] First, by running an algorithmic child pornography-directed binary search, the filter team would potentially satisfy the statutory requirement against turning over child pornography by segregating any data that falls within the statute.[156] Additionally, because the binary search does not fall within the Fourth Amendment, the government never becomes aware of potentially exculpatory evidence beyond that identified as responsive to the warrant, limiting Brady liability and reducing the digital evidence it must turn over.

Binary searches aside, a filter team reviewing materials would still preclude Brady issues. The team, acting within the warrant’s scope, would sift digital data into its various categories: Brady materials, data responsive to the warrant, and data nonresponsive to the warrant. New probable cause or prosecutorial action would be restricted, only arising from the materials sifted into the responsive category, satisfying Kerr’s concerns with intrusion into Fourth Amendment privacy interests. Under a Rule 41 motion, pursuant to a judge’s ex ante order or predicated on any future U.S. Supreme Court holdings, materials nonresponsive to the warrant can be returned.[157] The Ninth Circuit has already grappled with this and applied a system of evidentiary firewalls; by segregating data and instituting filter team search protocols, law enforcement serves the Fourth Amendment by protecting individual privacy interests.[158] Perhaps this provides a roadmap for the Court to follow.

C. Morton and the Evidentiary Firewall

Had the Texas DPS Troopers utilized an evidentiary firewall during their investigation of Morton, they would have only had access to evidence from his phones directly relating to the original warrant. That warrant only allowed searching for evidence of narcotics trafficking or possession.[159] A filter team would have limited the evidence it provided to the investigatory team to that approved under the warrant—evidence of drug possession or trafficking.

However, this does not mean Morton would have automatically gone free. Already suspicious of Morton’s behavior based on the presence of “children’s school supplies, a lollipop, fourteen sex toys, and one hundred pairs of women’s underwear in the vehicle,” the troopers would not have had the option to engage in a pretextual search of Morton’s phone.[160] Instead, the troopers would have needed to properly develop probable cause before obtaining a warrant to search his cell phones for child pornography. While this might add an investigatory burden on law enforcement in the future, this is the balance the Fourth Amendment requires.

VI. Conclusion

Kerr’s “ongoing seizure” use restriction has not gained traction within the court systems or the body of legal scholarship surrounding the Fourth Amendment. As seen in Ganias and Morton, courts often rely on the good-faith exception to circumvent opportunities where a use restriction might apply. After Mansor, Kerr indicated that a better-written warrant application would have precluded the Oregon high court’s opportunity to restrict use. Kerr admitted that law enforcement in Mansor developed enough probable cause from its first search to obtain a second warrant and broaden the scope. And finally, considering the government’s Brady obligations, any strong enforcement of Kerr’s approach would remove the possibility of creating new independent probable cause during a Brady examination. Under Kerr’s “ongoing seizure” use restriction, any exposure to additional criminal material becomes instantly suppressible, crippling subsequent investigations before they even start.

Instead, courts should rely on evidentiary firewalls via filter teams and algorithmic binary searches. Utilizing this approach removes the reliance on the good-faith exception, allows the body of digital search jurisprudence to develop free from a disproportionate balance of child pornography cases, and creates an avenue by which the government can easily satisfy its Brady requirements. The practice is already in use in governmental and privilege contexts where enhanced privacy interests exist. The Ninth Circuit has adopted a similar approach and has shown how it can protect privacy interests without sacrificing the government’s investigatory mandate. Digital data continues to expand its presence in the courts, and as Kerr noted, another Riley moment is due from the Supreme Court. But, with the Court denying certiorari in Morton v. United States, uncertainty remains.

Frank Chambers

  1. Riley v. California, 573 U.S. 373, 396 (2014) (quoting United States v. Kirschenblatt, 16 F.2d 202, 203 (2d Cir. 1926)). Writing in 1926 for the Second Circuit, Judge Hand illustrated the distinction between the volume of information available to authorities upon a general search of a person versus a home. Judge Hand summed up the opinion with a quote appropriate for the modern digital age: “[T]he whole of a man’s correspondence, his books of account, the record of his business, in general, the sum of his documentary property—these, in our judgment, are as inviolate upon his arrest as they certainly are upon search warrant.” Kirschenblatt, 16 F.2d at 204.

  2. Riley, 573 U.S. 373 at 396.

  3. See Kirschenblatt, 16 F.2d at 204 (discussing the origin of the Fourth Amendment); see also U.S. Const. amend. IV (“The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.”).

  4. See infra Part III.

  5. Riley, 573 U.S. at 381–82.

  6. See Ric Simmons, The Mirage of Use Restrictions, 96 N.C. L. Rev. 133, 137–38 (2017). Simmons provides a succinct backstory into how the collision of technological growth and government searches prompted Professor Harold Krent to propose “Use Restrictions” to limit data obtained by the government during searches. See generally Harold J. Krent, Of Diaries and Data Banks: Use Restrictions Under the Fourth Amendment, 74 Tex. L. Rev. 49 (1995).

  7. See, e.g., Riley, 573 U.S. at 386; Carpenter v. United States, 138 S. Ct. 2206, 2217 (2018) (holding that an individual maintains an expectation of privacy of records of movements captured by cell phones).

  8. See infra Section II.A for a discussion of Riley’s importance in the digital search context.

  9. See infra Part IV for a discussion of additional tools suggested to courts by scholars. See infra Part V for this Comment’s suggested use of evidentiary firewalls as the best navigational tool.

  10. Orin S. Kerr, Executing Warrants for Digital Evidence: The Case for Use Restrictions on Nonresponsive Data, 48 Tex. Tech L. Rev. 1, 24–25 (2015) (defining “ongoing seizure”). Professor Kerr, the William G. Simon Professor of Law at Berkley Law, has been credited as helping “found the field of computer crime law.” Orin Kerr, Berkley L., https://www.law.berkeley.edu/our-faculty/faculty-profiles/orin-kerr/ [https://perma.cc/NWE4-SGHL] (last visited Jan. 25, 2023).

  11. Kerr, supra note 10, at 24–25. For a more robust description of Kerr’s use restriction, see infra Section II.C.

  12. Infra Part III.

  13. Infra Part IV.

  14. Infra Part V.

  15. Simmons, supra note 6, at 138–39; see Krent, supra note 6, at 86–87 (expressing concern that states maintained data banks of DNA collected from “persons likely to commit violent crimes”). Under Krent’s proposal, subsequent use of legally seized information undisclosed to the owner or not implied from the original seizure became unreasonable under the Fourth Amendment. Id. at 85–86. Though he used examples of DNA and school locker searches, Krent acknowledged technology’s continued growth and law enforcement’s increasing reliance upon it. Id. at 57–58, 93, 97. Since Krent’s initial proposal, legal scholars have generally defined use restrictions as the means to constrain law enforcement’s use of information already legally within its possession, whether through constitutional, statutory, or regulatory action. Simmons, supra note 6, at 137; see also Krent, supra note 6, at 75 (“Use restrictions accommodate the government’s interest in obtaining information with individuals’ interest in confining disclosure of private information as much as possible.”); Orin S. Kerr, Use Restrictions and the Future of Surveillance Law, Brookings (Apr. 19, 2011), https://www.brookings.edu/articles/use-restrictions-and-the-future-of-surveillance-law/ [https://perma.cc/5PZE-QJ4B] (explaining use restrictions as “rules that strictly regulate what the government can do with information it has collected and processed”).

  16. Simmons, supra note 6, at 138–39. Simmons cites Kerr as believing in 2011 that use restrictions would originate from statutes, not from the Fourth Amendment. Id. at 136 n.8 (citing Kerr, supra note 15). However, in the Brookings article, Kerr acknowledges the possibility of ways to “creatively re-imagine Fourth Amendment law” to recognize use restrictions, citing Krent’s approach. Kerr, supra note 15. But Kerr was musing on large-scale government surveillance, not digital searches in the context of smaller, individualized investigations. Id. Though it would be another four years before Kerr published the article discussed in this Comment, he had already begun engaging with the ideas that would result in his “ongoing seizure” use restriction proposal. Id.

  17. Simmons, supra note 6, at 139 (noting that scholars have proposed use restrictions to protect individual privacy interests in arenas as diverse as big data, digital searches, drone surveillance, and national security data collection).

  18. See Andrew Guthrie Ferguson, Surveillance and the Tyrant Test, 110 Geo. L.J. 205, 265–66 (2021). Ferguson argues that tyranny served as a “framing fear of the constitutional order.” Id. at 266. The modern world must design legal structures to constrain digital intrusion into individual privacy to remain consistent with the “constitutional plan.” Id.

  19. Riley v. California, 573 U.S. 373, 385 (2014).

  20. Id. at 378–81.

  21. Id. at 379, 381. Police seized Riley’s cell phone incident to his arrest for driving with a suspended license, and in a subsequent search of his phone, discovered gang contacts, evidence of physical violence, and a photograph of Riley standing in front of a vehicle suspected in an earlier shooting. Id. at 378–79. After the trial court refused to suppress evidence obtained during that search, Riley was convicted of the charges predicated upon the search of his phone. Id. at 379–80. In the companion case, following an arrest after police witnessed a drug sale, a search of the suspect’s phone led police to his house, where a warranted search resulted in the seizure of drugs, cash, and weapons. Id. at 380–81.

  22. Id. at 393. The Court rejected the government’s assertion that a search of cell phone data is “materially indistinguishable” from physical searches. Id. The Court analogized the comparison between the two by suggesting that “a ride on a horseback is materially indistinguishable from a flight to the moon. Both are ways of getting from point A to point B, but little else justifies lumping them together.” Id. Any justification for privacy intrusions into digital data must “rest on its own bottom.” Id.

  23. Id. at 396–97. See supra note 1 for a discussion of Judge Learned Hand’s opinion in Kirschenblatt.

  24. Riley, 573 U.S. at 401.

  25. How Many Pages in a Gigabyte, LexisNexis, https://www.lexisnexis.com/applieddiscovery/lawlibrary/whitepapers/adi_fs_pagesinagigabyte.pdf [https://perma.cc/35VA-3Z29] (last visited Nov. 22, 2022); Jim Martin, How Many Megabytes Are There in a Gigabyte?, Tech Advisor (Feb. 3, 2023), https://www.techadvisor.com/article/727000/how-many-mb-in-a-gb.html [https://perma.cc/Z2AP-NQJS].

  26. United States v. Ganias, 824 F.3d 199, 218 (2d Cir. 2016) (quoting Quentin Hardy, As a Data Deluge Grows, Companies Rethink Storage, N.Y. Times (Mar. 14, 2016), https://www.nytimes.com/2016/03/15/technology/as-a-data-deluge-grows-companies-rethink-storage.html [https://perma.cc/Y5A3-HDG2].

  27. State v. Mansor, 421 P.3d 323, 331–32 (Or. 2018) (en banc) (discussing the significant reasons digital data and physical evidence differ). The court leans heavily on The Physical Computer and the Fourth Amendment, where the author likens a digital search to an archaeological dig or forensic pathology where certain data can reveal how the computer had been used in the past. Id.; see Josh Goldfoot, The Physical Computer and the Fourth Amendment, 16 Berkeley J. Crim. L. 112, 127 (2011). Different from a filing cabinet, a computer also stores information showing when users accessed data, how and through what connection points users accessed the Internet, what external data storage devices were attached, and when it occurred. Goldfoot, supra note 27, at 127–28. Additionally, computers store data showing when users created and deleted files, revealing hints of past memory. Id. Data valuable to forensic examiners is scattered throughout the storage medium. Id. at 128–29.

  28. Mansor, 421 P.3d at 332.

  29. Kerr, supra note 10, at 10–11; see also Emily Berman, Digital Searches, the Fourth Amendment, and the Magistrates’ Revolt, 68 Emory L.J. 49, 58 (2018) (noting that Federal Rule of Criminal Procedure 41 acknowledges overseizure). When adopting the rule for digital seizure, the 2009 Rules Advisory Committee stated: “This rule acknowledges the need for a two-step process: officers may seize or copy the entire storage medium and review it later to determine what electronically stored information falls within the scope of the warrant.” Fed. R. Crim. P. 41 advisory committee’s note to 2009 amendment.

  30. Orin S. Kerr, Searches and Seizures in a Digital World, 119 Harv. L. Rev. 531, 536–37 (2005); see U.S. Const. amend. IV (“[P]articularly describing the place to be searched, and the persons or things to be seized . . . .”).

  31. Kerr, supra note 10, at 7.

  32. Laurent Sacharoff, Unlocking the Fifth Amendment: Passwords and Encrypted Devices, 87 Fordham L. Rev. 203, 215–16 (2018) (noting that courts generally refuse to limit digital searches); Yuval Simchi-Levi, Search Warrants in the Digital Age, 47 Hofstra L. Rev. 995, 1002 (2019) (explaining that searches can rule out virus intrusion or corruption).

  33. Kerr, supra note 10, at 7–8; see United States v. Carey, 172 F.3d 1268, 1276 (10th Cir. 1999) (finding the search unreasonable). But cf. United States v. Mann, 592 F.3d 779, 786 (7th Cir. 2010) (finding the search reasonable); United States v. Johnston, 789 F.3d 934, 942–43 (9th Cir. 2015) (finding an expanded search reasonable).

  34. See Harris v. United States, 390 U.S. 234, 236 (1968) (holding that objects in plain view of an officer who is legally present are subject to search and seizure).

  35. See Simchi-Levi, supra note 32, at 1005–08 (discussing plain view caselaw in the digital context); see, e.g., United States v. Walser, 275 F.3d 981, 986–87 (10th Cir. 2001) (holding that discovery of child pornography outside the scope of the warrant falls within plain view exception); Mann, 592 F.3d at 786 (holding that discovery of child pornography falls within the plain view exception); United States v. Williams, 592 F.3d 511, 524 (4th Cir. 2010) (holding that discovery of child pornography fell within the plain view exception); cf. Carey, 172 F.3d at 1276 (suppressing evidence because of an unreasonable search outside the warrant); United States v. Comprehensive Drug Testing, Inc., 621 F.3d 1162, 1170–71 (9th Cir. 2010) (en banc) (holding that allowing plain view of anything seized by the government would incentivize mass unreasonable seizure).

  36. United States v. Morton, 46 F.4th 331 (5th Cir. 2022) (en banc).

  37. See Berman, supra note 29, at 90.

  38. United States v. Morton, 984 F.3d 421 (5th Cir. 2021), reh’g en banc granted, opinion vacated, 46 F.4th 331 (5th Cir. 2022) (en banc).

  39. Id. at 424.

  40. Id.

  41. Id.

  42. Id.

  43. Id.

  44. Id.

  45. Id.

  46. Id. at 431. Kerr noted his disagreement with the three-panel opinion, arguing that probable cause only relates to the substance of evidence, not the form that it takes. Orin S. Kerr, Remarkable New Fifth Circuit Decision Limiting Cell Phone Searches, Volokh Conspiracy (Jan. 10, 2021, 5:20 PM), https://reason.com/volokh/2021/01/10/remarklable-new-fifth-circuit-decision-limiting-cell-phone-searches/ [https://perma.cc/E243-5MUW]. However, he argues that the court reached the right result; had the court applied his version of use restriction, any evidence found outside the warrant would fall victim to suppression. Id. In essence, his approach disincentivizes a pretextual search for one thing (drugs, here) while targeting another (child pornography). Id.

  47. United States v. Morton, 46 F.4th 331, 339–40 (5th Cir. 2022) (en banc).

  48. Id. at 340–41 (Higginson, J., concurring) (quoting Boyd v. United States, 116 U.S. 616, 630 (1886)); see Riley v. California, 573 U.S. 373, 396–97 (2014).

  49. Morton, 46 F.4th at 341 (Higginson, J., concurring).

  50. Id. at 340–41 (citing Riley, 573 U.S. at 396–97) (“To my eye, that conception is unlikely to approve plain view full access to, and use of, what the Supreme Court has observed is more private information than would be contained in an entire home, where plain view access has obvious and significant limits.”).

  51. Kerr, supra note 10, at 20 (suggesting the need for a “Riley moment”); see Morton v. United States, 143 S. Ct. 559 (2023) (granting motion for leave to file petition for writ of certiorari). But see Order List: 598 U.S., SupremeCourt.gov 2–4, https://www.supremecourt.gov/orders/courtorders/051523zor_h315.pdf [https://perma.cc/Q82E-62T3] (last visited Aug. 24, 2023) (denying petition for certiorari).

  52. Kerr, supra note 10, at 10.

  53. Id. at 11. But see Kerr, supra note 30, at 582–83 (suggesting that as of 2005, the time for abolishing the plain view exception had not yet ripened).

  54. Kerr, supra note 10, at 22. See generally Orin S. Kerr, Fourth Amendment Seizures of Computer Data, 119 Yale L.J. 700 (2010), for a discussion of whether, because it fails to infringe on possessory interests, copying digital data constitutes a seizure.

  55. Kerr, supra note 10, at 11.

  56. Id. at 24; see also Krent, supra note 6, at 77–92 (arguing that subsequent use may be unreasonable under the Fourth Amendment).

  57. Kerr, supra note 10, at 22; United States v. Jacobsen, 466 U.S. 109, 111–12, 125 (1984).

  58. Jacobsen, 466 U.S. at 125 (holding that in this instance the balance favored the government).

  59. Kerr, supra note 10, at 25–26.

  60. Id.; see also U.S. Const. amend. IV (“[P]articularly describing the place to be searched, and the persons or things to be seized . . . .”).

  61. Kerr, supra note 10, at 26 (quoting Terry v. Ohio, 392 U.S. 1, 20 (1968)).

  62. Id. at 29.

  63. Id.

  64. Id.

  65. Id. at 29–30.

  66. United States v. Morton, 46 F.4th 331, 340–41 (5th Cir. 2022) (Higginson, J., concurring).

  67. United States v. Morton, 984 F.3d 421, 424 (5th Cir. 2021), reh’g en banc granted, opinion vacated, 46 F.4th 331 (5th Cir. 2022); see Riley v. California, 573 U.S. 373, 386 (2014) (holding that law enforcement generally cannot search cell phones seized incident to arrest without an additional warrant).

  68. Morton, 984 F.3d at 424.

  69. Id.; see Kerr, supra note 10, at 26; Kerr, supra note 46 (breaking down how he would apply the ongoing seizure restriction to the Morton facts).

  70. Morton, 984 F.3d at 424.

  71. Kerr, supra note 10, at 26.

  72. United States v. Morton, 46 F.4th 331, 339 (5th Cir. 2022) (en banc).

  73. See id. at 342–44 (Graves, J., dissenting). The dissent did not see how the troopers developed probable cause beyond drug possession predicated on finding “16 ecstasy pills, a small bag of marijuana, and a glass pipe.” Id. The application for a search warrant relied on “sweeping generalizations” and failed to provide a “nexus to the crime of simple possession.” Id. at 342–43. Beyond destroying probable cause to search Morton’s phone, the dissent also believes this would have removed the good faith relied on by the majority in excepting the troopers’ actions from the exclusionary rule. Id. at 343. The dissent sees this as an incentive for law enforcement to predicate substantial Fourth Amendment violations on “small quantities of illicit drugs for personal use during an automobile stop.” Id. at 344. In short, the majority renders Riley’s holding powerless because there are “virtually no costs against” violating it. Id.

  74. Infra Part III.

  75. Infra Section III.B.

  76. Kerr, supra note 10, at 31–32 (noting that the court would create an affirmative requirement to delete nonresponsive files rather than his suggestion to refrain from using them, rendering that approach difficult to implement). In United States v. Ganias, IRS investigators obtained a warrant to search data seized by the Army during an unrelated 2003 investigation, which the Army had never removed from evidence. United States v. Ganias, 755 F.3d 125, 130 (2d Cir. 2014), on reh’g en banc, 824 F.3d 199 (2d Cir. 2016). Because Ganias had purged his computer of relevant data after the Army’s initial seizure, the evidence later used to convict Ganias only existed in the retained data. Id. The court refused to suppress the evidence; a jury convicted Ganias of tax evasion. Id. The Second Circuit found the retention permissible under Rule 41, but because that data was nonresponsive to the original warrant, the court found its subsequent use violated the Fourth Amendment. Id. at 135–37; see Fed. R. Crim. P. 41. (permitting the seizure of “electronic storage media or the seizure or copying of electronically stored information”). Overseizure followed by indefinite retention effectively created a general warrant. Ganias, 755 F.3d at 139–40 (“The Fourth Amendment was intended to prevent the Government from entering individuals’ homes and indiscriminately seizing all their papers in the hopes of discovering evidence about previously unknown crimes.”); see also Birchfield v. North Dakota, 579 U.S. 444, 450, 464 (2016) (recognizing the difficulties with indefinite retention of physical data in striking down a North Dakota law imposing criminal penalties for refusing a blood test to show blood alcohol content); Simmons, supra note 6, at 192 (highlighting that even when courts apply a use restriction on retained evidence, the possibility of mistaken use or distribution remains).

  77. Kerr, supra note 10, at 25; United States v. Ganias, 791 F.3d 290, 290 (2d Cir. 2015) (granting en banc review).

  78. See supra Section II.B (discussing Morton); United States v. Ganias, 824 F.3d 199, 200 (2d Cir. 2016) (en banc). While the court acknowledged the difficulty faced by the government during digital searches, it noted Ganias never utilized available means to seek the return of the segregated documents. Ganias, 824 F.3d at 218–19; see Fed. R. Crim. P. 41(g) (describing the process by which “[a] person aggrieved by an unlawful search and seizure of property” may seek its return).

  79. Ganias, 824 F.3d at 220 n.42 (suggesting the dissent inaccurately reads Kerr’s support of the panel opinion). But see id. at 228 n.5 (Chin, J., dissenting) (noting a scholarly consensus “that the panel largely got it right”).

  80. United States v. Lofstead, 574 F. Supp. 3d 831, 836, 847 n.9 (D. Nev. 2021), appeal dismissed, No. 21-10375, 2022 WL 866324 (9th Cir. Jan. 4, 2022).

  81. United States v. Hulscher, No. 4:16-CR-40070-01-KES, 2017 WL 1294452, at *12 (D.S.D. Feb. 10, 2017).

  82. See id. at *3 (adopting the Magistrate’s recommendation with modifications). Though the district court omitted the magistrate’s suggestion of a use restriction, it acknowledged conflicts with Riley and the tendency of cell phone search warrants to trend toward general warrants. Id. at *2, *4. Law enforcement should have returned for a second warrant and should not have relied on the original warrant to search the phone’s entire contents. Id. at *2.

  83. Stevenson v. Maryland, 138 S. Ct. 705 (2018) (denying petition for certiorari without comment); see Petition for Writ of Certiorari at 25, Stevenson, 138 S. Ct. 705 (No. 17-796); see also Kerr, supra note 10, at 20 (“Under this doctrinal path, courts should identify another ‘Riley moment’ and rule that the plain view exception does not apply to the execution of digital search warrants.”).

  84. Brief of Amici Curiae Elec. Frontier Found. & Am. Civ. Liberties Union in Support of Defendant-Appellant at 16, United States v. Gartenlaub, 751 F. App’x 998 (9th Cir. 2018).

  85. Gartenlaub, 751 F. App’x at 1000 n.3.

  86. United States v. Sedaghaty, 728 F.3d 885, 914–15 (9th Cir. 2013). The court did not go so far as to label the whole search a “flagrant general search” and only excluded nonresponsive data. Id. at 915. But see id. at 922–23, 926 (Tallman, J., concurring in part) (finding first, that the majority’s disregard for the incorporated affidavit incorrectly narrowed the scope of the warrant, rendering the disputed evidence nonresponsive, and second, that even if the disputed evidence was nonresponsive, the majority should have applied the good faith exception to permit the evidence instead of remanding for consideration of whether the agents acted with good faith).

  87. See United States v. Morton, 46 F.4th 331, 341 (5th Cir. 2022) (Higginson, J., concurring).

  88. In setting the legal groundwork for its ruling, the Oregon high court referenced four different articles mentioned in Kerr. State v. Mansor, 421 P.3d 323, 332–33, 341 (Or. 2018). In applying the “use restriction,” the court explained:

    [W]hen the state conducts a reasonably targeted search of a person’s computer for information pursuant to a warrant that properly identifies the information being sought, the state has not unreasonably invaded the person’s privacy interest, and the state may use the information identified in the warrant in a prosecution or any other lawful manner. But when the state looks for other information or uncovers information that was not authorized by the warrant, Article I, section 9, prohibits the state from using that information at trial, unless it comes within an exception to the warrant requirement.

    Id. at 344.

  89. Id. at 327–28. The police sought to specifically corroborate Mansor’s claim that, for the fifteen minutes immediately preceding his 911 call to report that his son had stopped breathing, he had searched the Internet for remedies. Id.

  90. Id. at 328.

  91. Id.

  92. Id. at 329.

  93. Id. at 329–30.

  94. Id. at 343.

  95. Id. at 344.

  96. Orin Kerr, Oregon Supreme Court Adopts Use Restrictions on Nonresponsive Data for Computer Warrants, Reason: Volokh Conspiracy (June 29, 2018, 2:40 AM), https://reason.com/volokh/2018/06/29/oregon-supreme-court-adopts-use-restrict/ [https://perma.cc/2E8V-4LG2]. Kerr also noted that Oregon’s Constitution lacks a good faith exception, which, as the federal cases have shown, provides an out for courts when their hands appear tied by constitutional violations. Id.

  97. State v. Serrano, 527 P.3d 54, 62 (Or. Ct. App. 2023). While investigating claims that a man had filmed a sexual assault of an unconscious woman and uploaded it to pornography websites without her consent, law enforcement discovered additional victims within the responsive data obtained from the man’s cell phone. Id. at 57–58. Law enforcement obtained a second, broader warrant, from which they discovered two more adult victims and one underage victim. Id. at 58.

  98. Id. at 61.

  99. Id. at 62.

  100. Id. at 63.

  101. Id. at 63 n.6.

  102. Id. at 67–68 (Aoyagi, J., concurring); see also id. at 64 (majority opinion) (appearing to request the same thing of the high court by “acknowledg[ing] that the nuances of this area of law relating to digital searches are complex and developing”).

  103. McGraw v. State, No. 19A-CR-1029, 2020 WL 857034, 144 N.E.3d 219, *4, *9 (Ind. Ct. App. Feb. 21, 2020).

  104. Id. at *7, *9. The court found that in revoking McGraw’s probation, the trial court judge did not consider the nonresponsive evidence to reach its ruling. Id. at *7. Further, Indiana law did not prohibit that evidence’s consideration during sentencing, so the trial court holding had no effect. Id. at *9. Additionally, the court did not publish the decision preventing any potential precedent. Id. at *1.

  105. See Brief of Amici Curiae Am. Civ. Liberties Union Found., Am. Civ. Liberties Union of Wis. Found., Elec. Frontier Found., and Elec. Priv. Info. Ctr. at 20–21, State v. Burch, 961 N.W.2d 314 (Wis. 2021) (No. 2019-AP-1404-CR), 2021 WL 1041546; Burch, 961 N.W.2d 314, cert. denied, 142 S. Ct. 811 (2022) (ignoring the invitation to apply Mansor’s use restriction).

  106. Commonwealth v. Green, 204 A.3d 469, 482 (Pa. Super. Ct. 2019), aff’d, 265 A.3d 541 (Pa. 2021) (ignoring the suggestion to apply use restrictions); see Brief of Amici Curiae of the Am. Civ. Liberties Union, Am. Civ. Liberties Union of Pa., the Def. Ass’n of Philadelphia, and the Pa. Ass’n of Crim. Def. Laws. at 24, Commonwealth v. Green, 265 A.3d 541 (Pa. 2021) (No. 6 MAP 2021). Instead, that court found that the seized evidence presented at trial appropriately fit within the scope of the warrant. Green, 204 A.3d at 482.

  107. Commonwealth v. Johnson, 240 A.3d 575, 590 (Pa. 2020) (holding that the warrant lacked probable cause); see Brief of Amici Curiae the Am. Civ. Liberties Union of Pa. and the Pa. Ass’n of Crim. Def. Laws. at 23–26, Johnson, 240 A.3d 575 (No. 25 WAP 2019).

  108. Effy Folberg, Search Warrants for Digital Speech, 22 Yale J.L. & Tech. 318, 345 (2020).

  109. Id. at 345–46; see, e.g., People v. Hughes, 958 N.W.2d 98, 120–21 (Mich. 2020) (allowing evidence of nonresponsive data when discovered while engaged in reasonably directed search of responsive data); United States v. Loera, 923 F.3d 907, 920–21 (10th Cir. 2019) (holding that evidence of child pornography discovered during a reasonable search for computer fraud was admissible) (collecting cases).

  110. Hughes, 958 N.W.2d at 120 (engaging in a “totality-of-circumstances” analysis to determine reasonableness); Loera, 923 F.3d at 916–17 (focusing analysis on reasonableness of the search).

  111. Folberg, supra note 108, at 346–47.

  112. Kerr, supra note 96.

  113. See Simchi-Levi, supra note 32, at 1008; United States v. Morton, 984 F.3d 421, 430 (5th Cir. 2021), reh’g en banc granted, opinion vacated, 46 F.4th 331 (5th Cir. 2022).

  114. Kerr acknowledged this issue in 2011 when advocating for statutory use restrictions as opposed to a court-imposed regiment originating in the Fourth Amendment. See Kerr, supra note 15, at 10. He noted that “[t]he kind of fine-grained reasonableness inquiry called for by Fourth Amendment law would leave judges with few clear guide-posts to distinguish uses that violate the Fourth Amendment from those that don’t with no historical precedent to follow.” The result, he conceded, would be that “recognizing use restrictions in Fourth Amendment law may create more problems than it solves.” Id. The difference between Kerr’s thoughts in 2011 and those in 2015 turns on the Supreme Court’s 2014 opinion in Riley, which provided a way forward. Kerr, supra note 10, at 10 (“In a recent decision, Riley v. California, the Supreme Court adopted a new approach to computer search and seizure law.” (emphasis added)). Perhaps this was what it would take to “expect courts to take such a leap” and apply use restrictions in the Fourth Amendment context. Kerr, supra note 15.

  115. Kerr, supra note 96.

  116. See supra Section II.B for a discussion of Morton and the problem of child pornography in the digital search context. See also supra note 35 for a discussion of cases in the child pornography context.

  117. Berman, supra note 29, at 90.

  118. Id. at 68, 70.

  119. Id. at 84 (quoting 50 U.S.C. § 1801(h)(1) (2012)).

  120. Id. at 70, 82–85; see also Simmons, supra note 6, at 164 (describing the national security approach to searching data as one where you must obtain a fishing license before casting a line into the pond).

  121. Berman, supra note 29, at 84.

  122. Id. at 65 n.76, 80.

  123. Id. at 86.

  124. Id. at 90; see also Kerr, supra note 96 (suggesting law enforcement did not expect the Mansor court to read the warrant so narrowly).

  125. Berman, supra note 29, at 90.

  126. Id. at 91.

  127. Id. at 61–62 (describing the ex ante approach magistrates already use to prescribe search protocols to prevent digital searches from extending too broadly). But see State v. Mansor, 421 P.3d 323, 332 (Or. 2018) (expressing concern that reliance on metadata to restrict digital searches during search protocols fails to limit those searches due to potential data manipulation); see also Kerr, supra note 10, at 16 (“Data can always be changed.”); Sacharoff, supra note 32, at 215 (noting that law enforcement often searches all data under the theory criminals manipulate metadata). Further, Kerr has addressed his distrust for ex ante restrictions in a previous article. See generally Orin Kerr, Ex Ante Regulation of Computer Search and Seizure, 96 Va. L. Rev. 1241 (2010). His concern arises from a general belief that magistrates cannot see into the future to predict constitutional reasonableness. Kerr, supra note 10, at 13. In his view, magistrates will impose “their own arbitrary restrictions.” Id. A better approach, he insists, is one in which the “law of reasonableness” develops through usual appellate review. Id. at 14.

  128. See Brady v. Maryland, 373 U.S. 83, 87 (1963). Brady and its line of cases created a requirement that the government turn over material evidence favorable to the defense, with the Supreme Court requiring some evidence turned over by default, and other evidence only after a request that includes evidence related to witness impeachment. See, e.g., id.; United States v. Agurs, 429 U.S. 97, 106–07 (1976) (holding that the duty to hand over exculpatory evidence arises from the nature of the evidence); United States v. Bagley, 473 U.S. 667, 676 (1985) (holding that impeachment evidence falls within Brady because it can “make the difference between conviction and acquittal”); Kyles v. Whitley, 514 U.S. 419, 437–38 (1995) (holding that prosecutors have a duty to learn of Brady evidence from “others acting on the government’s behalf in the case, including the police”).

  129. Folberg, supra note 108, at 340.

  130. Id. at 339.

  131. Id.; see 18 U.S.C. § 3509(m).

  132. Folberg, supra note 108, at 339.

  133. Id. at 348–49.

  134. Id. at 386–87 (referring to the search of presidential papers or when the government executes a search warrant for an attorney’s office).

  135. Supra Section IV.B.

  136. Berman, supra note 29, at 81; see Fed. R. Crim. P. 41(b), (e) (allowing the seizure of all physical storage devices within the warrant for later review).

  137. U.S. Dep’t of Just., Just. Manual § 9-13.420 (2018), https://www.justice.gov/jm/jm-9-13000-obtaining-evidence [https://perma.cc/Z2WL-A49B].

  138. Id. § 9-13.420(C).

  139. Id.

  140. Searching and Seizing Computers and Obtaining Electronic Evidence in Criminal Investigations, Off. of Legal Educ. Exec. Off. for U.S. Att’ys 110–11 (2009), https://www.justice.gov/file/442111/download [https://perma.cc/9EWJ-2Z5P].

  141. Id. at 110.

  142. Id.

  143. Id. at 111.

  144. Simmons, supra note 6, at 167–68.

  145. Id.

  146. See supra Section IV.A.

  147. Berman, supra note 29, at 89.

  148. See United States v. Morton, 46 F.4th 331, 336 (5th Cir. 2022) (en banc) (relying on the good-faith exception to uphold the search that discovered child pornography on Morton’s phone); see also supra note 35 (providing a list of cases in which courts found exceptions to the exclusion rule in child pornography cases).

  149. Simmons, supra note 6, at 175–76.

  150. Illinois v. Caballes, 543 U.S. 405, 408 (2005).

  151. Id. at 410.

  152. Simmons, supra note 6, at 176.

  153. Id. at 177.

  154. See Caballes, 543 U.S. at 410.

  155. See supra Section IV.C, for a discussion of the problem “ongoing seizure” use restriction creates for law enforcement’s Brady obligations. See Folberg, supra note 108, at 339–40, 348–49, for a more in-depth discussion of the “Digital Disclosure Trilemma.”

  156. But see Folberg, supra note 108, at 339 n.113 (expressing concern whether a machine algorithm, which identified child pornography at a near-90% rate in 2017, would sufficiently satisfy the statutory requirement of “shall remain”).

  157. Fed. R. Crim. P. 41(g) (permitting return of seized digital materials upon motion).

  158. Folberg, supra note 108, at 336–38; United States v. Comprehensive Drug Testing, Inc., 621 F.3d 1162, 1177 (9th Cir. 2010) (en banc).

  159. United States v. Morton, 984 F.3d 421, 424 n.1 (5th Cir. 2021), reh’g en banc granted, opinion vacated, 46 F.4th 331 (5th Cir. 2022).

  160. Id. at 424.