Amicus Curiae Brief — Aaron Rayshan Wells, Petitioner v. Texas
Supreme Court briefNov 19, 2025
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No. 25-484
IN THE
Supreme Court of the United States
__________
AARON RAYSHAN WELLS,
Petitioner,
v.
STATE OF TEXAS,
Respondent.
__________
On Petition for a Writ of Certiorari
to the Texas Court of Criminal Appeals
__________
BRIEF OF
FORMER MAGISTRATE JUDGE ANDREW AUSTIN
AS AMICUS CURIAE
IN SUPPORT OF GRANTING THE PETITION
__________
ALEJANDRA ÁVILA
Counsel of Record
MATTHEW J. WILKINS
NOELLE SUAREZ-MURIAS*
SPENCER R. LOCKWOOD**
KELLOGG, HANSEN, TODD,
FIGEL & FREDERICK, P.L.L.C.
1615 M Street, N.W., Suite 400
Washington, D.C. 20036
(202) 326-7900
(aavila@kellogghansen.com)
November 19, 2025
* Admitted to practice only in Illinois;
work supervised by members of the Firm
** Admitted to practice only in Texas;
work supervised by members of the Firm
TABLE OF CONTENTS
Page
TABLE OF AUTHORITIES ...................................... iii
INTEREST OF AMICUS CURIAE ............................ 1
INTRODUCTION AND SUMMARY OF
ARGUMENT .......................................................... 2
ARGUMENT ............................................................... 4
I. MAGISTRATE
JUDGES
NEED
GUIDANCE
ON
THE
FOURTH
AMENDMENT’S APPLICATION TO
GEOFENCE WARRANTS ............................... 4
A. Magistrate Judges Are The Last Line
Of Defense Against Unconstitutional
Searches ...................................................... 4
B. To Prevent Unlawful Searches,
Magistrate Judges Need Clear
Fourth Amendment Standards .................. 7
C. Magistrate Judges Face An Exponentially Increasing Number Of Applications For Geofence Warrants ................... 10
II. NO SOURCE CURRENTLY GIVES
MAGISTRATE JUDGES THE GUIDANCE THEY NEED ...................................... 11
A. This Court’s Precedents Offer Little
Guidance ................................................... 11
B. Lower Courts Are Hopelessly Divided ...... 12
C. Legislation Offers Little Guidance........... 15
D. Scholars Are As Divided As The
Courts ........................................................ 17
ii
III. ONLY THIS COURT CAN PROVIDE
THE
GUIDANCE
MAGISTRATE
JUDGES NEED ............................................. 18
A. Permitting Further Percolation Is
Futile ......................................................... 18
B. Legislatures Cannot Provide The
Needed Guidance ...................................... 19
C. This Court Must Provide The Needed
Guidance ................................................... 21
CONCLUSION.......................................................... 21
APPENDIX ............................................................... 1a
iii
TABLE OF AUTHORITIES
Page
CASES
Carpenter v. United States, 585 U.S. 296 (2018) ...... 11,
12, 20, 21
Jones v. State, 913 S.E.2d 700 (Ga. 2025) ................ 14
Shadwick v. City of Tampa, 407 U.S. 345 (1972) .... 4, 5
Smith v. Maryland, 442 U.S. 735 (1979) ................. 11
Snope v. Brown, 145 S. Ct. 1534 (2025) ................... 18
State v. Contreras-Sanchez, 5 N.W.3d 151
(Minn. Ct. App. 2024) .......................................... 15
United States v. Chatrie, 136 F.4th 100 (4th Cir.
2025), pet. for cert. pending, No. 25-112
(U.S.) .................................................................... 13
United States v. Davis, 109 F.4th 1320 (11th
Cir. 2024), pet. for cert. pending, No. 25-5189
(U.S.) .................................................................... 14
United States v. Fuentes, 2024 WL 5494054
(Sept. 3, 2024), report and recommendation
adopted, 2025 WL 484628 (Feb. 13, 2025),
recon. denied, 2025 WL 1042177 (E.D. Okla.
Apr. 8, 2025) ........................................................ 15
United States v. Leon, 468 U.S. 897 (1984)................ 7
United States v. McCracken, 2025 WL 3034953
(E.D. Pa. Oct. 30, 2025) ....................................... 15
United States v. Miller, 425 U.S. 435 (1976) ........... 11
United States v. Smith, 110 F.4th 817 (5th Cir.
2024), cert. denied, No. 24-7237 (U.S. Nov.
10, 2025) ........................................................... 7, 13
iv
CONSTITUTION, STATUTES, AND RULES
U.S. Const. amend. IV ............................ 1-4, 6-7, 9-11,
13-14, 17-18, 20-21
Communications Assistance for Law Enforcement Act, Pub. L. No. 103-414, tit. I, 108
Stat. 4279 (1994) ................................................. 16
Electronic Communications Privacy Act, Pub.
L. No. 99-508, 100 Stat. 1848 (1986) .............15, 16
Federal Courts Study Committee Implementation Act of 1990, Pub. L. No. 101-650, tit. III,
§ 321, 104 Stat. 5089, 5104, 5117 ...................... 4-5
Stored Communications Act, Pub. L. No. 99508, tit. II, § 201, 100 Stat. 1848, 1860
(1986) ................................................................... 20
USA PATRIOT Act, Pub. L. No. 107-56, 115 Stat.
272 (2001) ............................................................ 16
28 U.S.C. § 631(a) ....................................................... 4
Alaska Stat.:
§ 22.15.100(4) ......................................................... 9
§ 22.15.160(b) ......................................................... 9
Me. Rev. Stat. tit. 16, § 648 ...................................... 16
Minn. Stat. § 626A.42(2)........................................... 16
Mont. Code § 46-5-110 .............................................. 16
N.H. Rev. Stat. § 644-A:2 ......................................... 17
12 R.I. Gen. Laws § 32-2 ........................................... 17
Utah Code:
§ 77-23c-102 ......................................................... 17
§ 77-23f-102 ......................................................... 17
v
Vt. Stat. tit. 13:
§ 8101(8) ............................................................... 17
§ 8102 ................................................................... 17
Va. Code:
§ 19.2-33 ................................................................. 4
§ 19.2-35 ................................................................. 9
§ 19.2-37(B) ............................................................ 9
§ 19.2-45(2) ........................................................ 4, 9
Fed. R. Crim. P.:
Rule 4.1 .................................................................. 5
Rule 41(a)(1) .......................................................... 5
Rule 41(d) ............................................................... 5
Rule 41(d)(3) .......................................................... 5
Rule 41(g) ............................................................... 5
Sup. Ct. R.:
Rule 37.2(a) ............................................................ 1
Rule 37.6 ................................................................ 1
LEGISLATIVE MATERIALS
S.B. S404, 2025-2026 Legis. Reg. Sess. (N.Y
Jan. 8, 2025) ........................................................ 20
ADMINISTRATIVE MATERIALS
Admin. Off. of the U.S. Courts:
Status of Magistrate Judge Positions and
Appointments — Judicial Business 2024,
https://perma.cc/7FN3-55ZA .............................. 7-8
vi
The Selection, Appointment, And Reappointment Of United States Magistrate Judges
(2010), https://perma.cc/5YYT-VLYC .............. 9-10
U.S. Magistrate Judges — Judicial Business
2024, https://perma.cc/7EWD-ALJT ..................... 8
Report of the Proceedings of the Judicial Conference of the United States (Mar. 11, 2025),
https://perma.cc/BZ3N-2DBL ................................ 8
OTHER MATERIALS
Haley Amster & Brett Diehl, Note, Against
Geofences, 74 Stan. L. Rev. 385 (2022) ....17, 19, 20
Apple, Apple Reinvents the Phone with iPhone
(Jan. 9, 2007), https://perma.cc/E5JQ-EH9L ..... 16
Peter G. Berris & Clay Wild, Cong. Rsch. Serv.,
Geofence Warrants: A Circuit Split on
Application of the Fourth Amendment (Feb.
27, 2025) ..........................................................19, 20
CERN, The birth of the Web, https://perma.cc/
NG82-HHB6 ........................................................ 15
Miguel F.P. de Figueiredo, Brett Hashimoto &
Dane Thorley, Unwarranted Warrants? An
Empirical Analysis of Judicial Review in
Search and Seizure, 138 Harv. L. Rev. 1959
(2025) ..................................................................... 8
Google:
From the garage to the Googleplex, https://
perma.cc/9UZW-2EHQ ......................................... 16
Supplemental Information on Geofence
Warrants in the United States, https://perma.
cc/9S8C-8ZFQ ...................................6, 9, 10, 16, 17
vii
Peter G. McCabe, A Guide to the Federal Magistrate Judges System (updated Oct. 2016),
https://perma.cc/U9SD-KUMY .......................... 5, 9
Note, Geofence Warrants and the Fourth
Amendment, 134 Harv. L. Rev. 2508 (2021)....... 17
Brian L. Owsley, The Best Offense Is a Good
Defense: Fourth Amendment Implications of
Geofence Warrants, 50 Hofstra L. Rev. 829
(2022) ..............................................................10, 16
Project for Privacy & Surveillance Accountability, Geofence Warrants and the Grand
Canyon of Circuit Splits (Aug. 20, 2024),
https://perma.cc/NG78-5GHD .............................. 13
Reed Sawyers, For Geofences: An Originalist
Approach to the Fourth Amendment, 29 Geo.
Mason L. Rev. 787 (2022) .................................... 17
Jordan Wallace-Wolf, Unfenced: The Fourth
Circuit Gives Geofencing Its First Appellate
Go-Ahead in United States v. Chatrie,
82 Wash. & Lee L. Rev. Online 1 (2024)............. 18
INTEREST OF AMICUS CURIAE 1
Amicus former Magistrate Judge Andrew Austin
served on the U.S. District Court for the Western
District of Texas from 1999 to 2021. In that capacity,
he ruled on thousands of applications for search
warrants, many of which sought to obtain digital
data from third parties—including applications for
geofence warrants.
He therefore experienced
firsthand the difficulties that magistrate judges face
daily applying Fourth Amendment principles to
geofence warrants and to requests for digital data
more broadly.
Since leaving the bench, amicus has served as an
adjunct professor at the University of Texas School of
Law, where he teaches a course called The Fourth
Amendment and Digital Data.
Amicus takes no position on how the Court should
decide this case but urges that the Court decide it.
Magistrate judges, who review geofence warrants
every day, need clarity on whether and how the
Fourth Amendment applies to those warrants. This
case gives the Court the opportunity to solve this
discrete, recurring, and intractably fractured constitutional issue.
1 Pursuant to Supreme Court Rule 37.6, counsel for amicus
represent that they authored this brief in its entirety and that
none of the parties or their counsel, nor any other person or entity
other than amicus or his counsel, made a monetary contribution
intended to fund the preparation or submission of this brief.
Pursuant to Rule 37.2(a), counsel for amicus also represent that
all parties were provided notice of amicus’s intention to file this
brief at least 10 days before it was due.
2
INTRODUCTION AND
SUMMARY OF ARGUMENT
Every day, magistrate judges around the country
receive dozens of applications for geofence warrants.
These warrants require technology companies to provide information on every device present in a defined
area during a set time frame. Law enforcement typically uses them when they know roughly when and
where a crime occurred but cannot identify a suspect.
These geofence warrants pose significant constitutional questions: Are geofence warrants unconstitutional general warrants? Do individuals have a
reasonable expectation of privacy in the location data
held by technology companies? If so, is that reasonable expectation absolute, or does it depend on the
scope of the requested geofence? What does it mean
to give digital data to technology companies willingly?
And many more.
Every day, magistrate judges around the country
struggle with these questions. They have little to
guide them, and what little they have is riddled with
conflicts and contradictions. The stakes, meanwhile,
are high. Geofence warrants are an increasingly prevalent tool for law enforcement, and they impact thousands of Americans. Wrong answers either unfairly
hamper law enforcement efforts or violate the Fourth
Amendment rights of untold numbers of persons.
The Court should grant certiorari to give magistrate
judges the guidance they need to answer these
important questions and protect Fourth Amendment
rights.
I. Magistrate judges need clear guidance on how
to apply the Fourth Amendment to applications for
geofence warrants. As the officials who consider and
3
issue warrants, magistrate judges are the final safeguards for preventing unconstitutional searches. Yet
many state-level magistrate judges are not lawyers,
and all magistrate judges considering warrant applications must rule quickly and largely without the benefit of legal briefing, relying instead on their own
knowledge of the law. Only with clear Fourth Amendment standards can magistrate judges reliably do so.
II. Magistrate judges currently have nowhere to
turn for the clear guidance they need.
Magistrate judges cannot find the answers they
need in this Court’s precedents. This Court has never
considered geofence warrants before and has explicitly left unanswered key questions about how the
third-party doctrine applies when individuals opt in to
provide data to technology companies.
Nor can magistrate judges turn to the lower courts
for help. An intractable circuit split exists between
the Fifth and Fourth Circuits. The Fifth Circuit says
geofence warrants are always unconstitutional, and
the Fourth Circuit says they do not even constitute
searches. Meanwhile, the Eleventh Circuit and the
Georgia Supreme Court have found that some but
not all geofence warrants are constitutional. The
Texas Court of Criminal Appeals’ decision below only
entrenched this divide, creating a jurisdictional split
within the Fifth Circuit at the federal and state levels.
Legislation and legal scholarship likewise provide
no answers. Legislatures have been largely silent on
the question of geofence warrants. And scholars are
as divided as the courts.
III. Only this Court can provide magistrate judges
the guidance they need, and the timing is right to do
so. The five appellate courts implicated in this split
have generated more than 15 opinions between them,
4
so further percolation is unlikely either to unify them
or to generate new ideas. And legislatures and scholars lack authority to say what the Fourth Amendment
requires. The time has therefore come for this Court
to provide further direction to the magistrate judges
who are the first and—in the vast majority of cases—
the last line of defense of the public’s Fourth Amendment rights.
ARGUMENT
I. MAGISTRATE JUDGES NEED GUIDANCE
ON THE FOURTH AMENDMENT’S APPLICATION TO GEOFENCE WARRANTS
A. Magistrate Judges Are The Last Line Of
Defense Against Unconstitutional Searches
The Fourth Amendment protects the people
“against unreasonable searches.” U.S. Const. amend.
IV. It does so by requiring the government to obtain
a warrant before conducting a search and to justify
that warrant by showing “probable cause” and by
“particularly describing the place to be searched, and
the . . . things to be seized.” Id. Magistrate judges
are tasked with determining whether the government
has satisfied those constitutional standards and, if
so, issuing the warrant.2 See Shadwick, 407 U.S. at
348-50.
2 For simplicity, amicus will use the term “magistrate judge”
to describe all officers who consider warrant applications at all
levels of government. At the state level, many officials who
are not judges review warrant applications. See, e.g., Va. Code
§ 19.2-33 (creating the “office of magistrate”); id. § 19.2-45(2)
(empowering “[a] magistrate . . . [t]o issue search warrants”). By
contrast, federal magistrate judges are appointed judicial officers. See 28 U.S.C. § 631(a) (creating the office of “United States
magistrate judges”); Federal Courts Study Committee Implementation Act of 1990, Pub. L. No. 101-650, tit. III, § 321, 104
5
The life cycle of a warrant proceeds in two basic
steps that culminate with the magistrate judge. First,
a law enforcement officer or government attorney
submits an application for a warrant, accompanied
by affidavits or other sworn testimony in support.
See Fed. R. Crim. P. 41(d).3 This application is often
made in writing but may be made orally, even over the
telephone. See Fed. R. Crim. P. 4.1, 41(d)(3). Second,
the magistrate judge evaluates the application for
probable cause and particularity based only on the
sworn testimony before him. See Fed. R. Crim. P.
41(a)(1), (d). If the warrant satisfies those constitutional prerequisites, then the magistrate judge issues
it. Only then can law enforcement execute the warrant and conduct a search. In other words, the magistrate judge is the last line of defense for preventing
unconstitutional searches before they happen.
Post-search judicial review of the warrant cannot
substitute for a magistrate judge’s adequate presearch review. As an initial matter, most warrants
are never reviewed by a higher court. Such review
occasionally occurs through motions to suppress or,
more rarely, through motions for the return of seized
property under Federal Rule of Criminal Procedure
41(g). Amicus estimates that higher courts reviewed
Stat. 5089, 5104, 5117 (“After the enactment of this Act, each
United States magistrate appointed under section 631 of title 28,
United States Code, shall be known as a United States magistrate judge[.]”). These titular differences, however, are legally
irrelevant. See Shadwick v. City of Tampa, 407 U.S. 345, 350
(1972) (“The substance of the Constitution’s warrant requirements does not turn on the labeling of the issuing party.”).
3 See also Peter G. McCabe, A Guide to the Federal Magistrate
Judges System 23-24 (updated Oct. 2016) (“Magistrate Judges
System Guide”), https://perma.cc/U9SD-KUMY.
6
far fewer than 10% of the warrants he issued in his
career.
Reviewing warrants for digital data in the possession of third parties is especially rare. In such cases,
the target of the search may never know that the
search—assuming it is a search within the meaning
of the Fourth Amendment—ever occurred, making
review even less likely.
Geofence warrants are particularly likely to evade
review. As petitioner explains, see Pet. 5-6, the
government has no specific suspect at the outset. It
only hopes that the geofence location data will reveal
a suspect. If the geofence location data does not reveal
one, however, then an untold number of people will
have been subject to a search (again, assuming it is a
search) of which they may never know. The nature of
geofence warrants therefore often leaves no one to
challenge the search to vindicate Fourth Amendment
rights.
Statistics bear this out. Magistrate judges have
issued tens of thousands—likely hundreds of thousands—of geofence warrants.4 Yet, as of the date
of this filing, a search for “(geofence /p warrant) OR
(‘reverse location’ /p warrant)” across all jurisdictions
returns just 92 cases in Westlaw.
Even in the rare case that a higher court reviews an
erroneously issued geofence warrant, the good-faith
exception to the exclusionary rule makes it unlikely
that the target of the unlawful search will receive any
relief. Under that exception, courts will not exclude
4 Google alone responded to more than 20,000 geofence warrants from 2018-2020. See Google, Supplemental Information on
Geofence Warrants in the United States (“Google Supplemental
Information”), https://perma.cc/9S8C-8ZFQ (last visited Nov. 17,
2025).
7
“evidence obtained in objectively reasonable reliance
on a subsequently invalidated search warrant” because
“a warrant issued by a magistrate normally suffices to
establish that a law enforcement officer has acted in
good faith in conducting the search.” United States v.
Leon, 468 U.S. 897, 922 (1984) (internal quotation
marks omitted). Thus, when a magistrate judge issues
a warrant, evidence derived from the resulting search
is often admissible even if the magistrate judge issued
the warrant erroneously and the search violated the
Fourth Amendment. See, e.g., United States v. Smith,
110 F.4th 817, 840 (5th Cir. 2024) (applying good-faith
exception even after finding geofence warrants per se
unconstitutional), cert. denied, No. 24-7237 (U.S. Nov.
10, 2025).
In sum, erroneously issued geofence warrants
potentially impacting the Fourth Amendment rights
of thousands of Americans are highly likely to evade
judicial review. The adequacy of magistrate judges’
pre-search review of geofence warrants is therefore
critically important.
B. To Prevent Unlawful Searches, Magistrate
Judges Need Clear Fourth Amendment
Standards
This Court should provide much-needed constitutional guidance for magistrate judges’ pre-search review.
Without clear legal standards, magistrate judges
cannot adequately protect Fourth Amendment rights.
First, the exigencies and time pressure that
accompany warrant applications—often requiring
magistrate judges to make on-the-fly assessments—
necessitate clear legal rules. In 2024 alone, 5695
5 See Admin. Off. of the U.S. Courts, Status of Magistrate
Judge Positions and Appointments—Judicial Business 2024,
8
active, full- and part-time federal magistrate judges
collectively ruled on more than 208,000 warrant
applications.6 That amounts to about one warrant
application per magistrate judge per day, in addition to
their many other duties. Indeed, “magistrate judges
disposed of 1,349,904 matters” in 2024, of which less
than one-sixth were warrant applications.7 Magistrate
judges simply do not have very much time in which to
review warrant applications. One study found “that
the median time for review is only three minutes, and
that one out of every ten warrants is opened, reviewed,
and approved in sixty seconds or less.”8 Clear legal
standards are thus necessary in light of the timesensitive reality of warrant applications.
Second, clear rules are needed because magistrate
judges considering warrant applications typically
receive no briefing on the law and must rely on their
own pre-existing knowledge. Warrant applications by
law enforcement contain only factual assertions, not
explanations of legal standards. The warrant application here is illustrative: it describes the persons,
things, or places to be searched, see App. 107a-109a,
https://perma.cc/7FN3-55ZA (last visited Nov. 17, 2025); Report
of the Proceedings of the Judicial Conference of the United States
14 (Mar. 11, 2025) (noting receipt of “569 annual reports from
magistrate judges” as of December 13, 2024), https://perma.
cc/BZ3N-2DBL.
6 See Admin. Off. of the U.S. Courts, U.S. Magistrate Judges—
Judicial Business 2024, https://perma.cc/7EWD-ALJT (last visited Nov. 17, 2025).
7
See id. (observing that “magistrate judges disposed of
1,349,904 matters” in 2024, of which just 208,366 were “search
warrant applications,” and 1,349,904 / 208,366 = 6.48).
8 Miguel F.P. de Figueiredo, Brett Hashimoto & Dane Thorley,
Unwarranted Warrants? An Empirical Analysis of Judicial Review in Search and Seizure, 138 Harv. L. Rev. 1959, 1960 (2025).
9
and recites facts that purport to establish probable
cause, see App. 112a-114a. It is not a legal brief—it
contains no section on the applicable legal standards
for geofence warrants, let alone the nuances of the
existing circuit split.
Magistrate judges likewise receive no legal briefing
from the target of the warrant. Magistrate judges consider all warrant applications ex parte. See Magistrate
Judges System Guide at 23. So the target of the
warrant could provide no briefing or argument even if
it wanted to.
Third, clear standards are necessary because
magistrate judges’ qualifications vary widely across
jurisdictions, with many States not requiring that
magistrate judges be lawyers or even have gone to
law school. Virginia, for example, requires only that
magistrate judges “have a bachelor’s degree,” Va. Code
§ 19.2-37(B), and not have “a criminal conviction for a
felony,” id. § 19.2-35. See also id. § 19.2-45(2) (power
to issue search warrants). Alaska requires only that
a magistrate judge be a citizen of the United States,
at least 21 years old, and a resident of Alaska for
at least six months. See Alaska Stat. § 22.15.160(b);
see also id. § 22.15.100(4) (power to issue search
warrants).
Fourth Amendment standards must therefore be
sufficiently clear for non-lawyer magistrate judges
to apply them quickly and consistently. This is
especially so because state, not federal, magistrate
judges issue most geofence warrants. See Google
Supplemental Information at 2. And while federal
magistrate judges must be experienced lawyers in
good standing,9 even magistrate judges (and judges on
9 See Admin. Off. of the U.S. Courts, The Selection, Appointment, And Reappointment Of United States Magistrate Judges
10
higher courts) with law degrees and legal experience
have struggled to apply Fourth Amendment principles
to applications for geofence warrants. See infra Part
II.B.
C. Magistrate Judges Face An Exponentially
Increasing Number Of Applications For
Geofence Warrants
Geofence warrants are a powerful investigatory
innovation that have quickly become a favorite tool
of law enforcement. “The government filed its first
geofence search warrant in 2016.” Brian L. Owsley,
The Best Offense Is a Good Defense: Fourth Amendment Implications of Geofence Warrants, 50 Hofstra L.
Rev. 829, 834 (2022). Since then, their use has become
ubiquitous.
Google’s experience with geofence warrants is
illustrative. In 2018, Google received 982 geofence
warrants. See Google Supplemental Information. By
2019, that number increased to 8,396. See id. And, in
2020, that number ballooned to 11,554, amounting to
more than 30 per day and “constituting more than
25% of all warrants [Google] receive[s] in the United
States.” Id. at 1.
Given the ever-increasing prevalence and importance of geofence warrants, magistrate judges need to
know whether those warrants implicate the Fourth
Amendment and, if so, how.
9-10 (2010) (an applicant “must be . . . a member in good standing
of the bar of the highest court” of a jurisdiction and “have actively
practiced law for at least five years”), https://perma.cc/5YYTVLYC.
11
II. NO SOURCE CURRENTLY GIVES MAGISTRATE JUDGES THE GUIDANCE THEY
NEED
A. This Court’s Precedents Offer Little Guidance
This Court’s precedents do not provide the clarity
magistrate judges need to evaluate applications for
geofence warrants (or other warrants for digital data
held by third parties) quickly and consistently.
The Court’s only decision applying the Fourth
Amendment in the context of digital location data held
by a third party, Carpenter v. United States, 585 U.S.
296 (2018), is seven years old. In Carpenter, the Court
held that “[t]he Government’s acquisition of ” seven
days’ worth of “cell-site records . . . was a search under
[the Fourth] Amendment,” and so “the Government
will generally need a warrant to access” that data. Id.
at 319-20. In doing so, the Court revisited what had
until then been a widely accepted and easily applied
understanding—“individuals have no Fourth Amendment interests in” information “possessed, owned, and
controlled by a third party.” Id. at 321 (Kennedy, J.,
dissenting) (citing United States v. Miller, 425 U.S.
435 (1976); Smith v. Maryland, 442 U.S. 735 (1979)).
Having held that the third-party doctrine is not
absolute in the digital era, the Court provided little
forward-looking guidance on how to evaluate warrants—like geofence warrants—seeking data in the
possession of third parties. Indeed, the opinion provides little guidance by design: The Court emphasized
that its decision was “a narrow one” limited to the
specific technology at issue (cell-site location information) so as not to “embarrass the future.” Id. at 316
(majority). “[A] warrant is required in the rare case
where the suspect has a legitimate privacy interest
12
in records held by a third party.” Id. at 319. And to
identify those rare cases, the Court established a
procedure by which courts must, for every “qualitatively different category of ” information, assess anew
whether a reasonable expectation of privacy exists
based on the “depth, breadth, and comprehensive
reach” of the information sought, as well as the
“nature of its collection.” Id. at 309, 320.
Applying that test to geofence warrants has bedeviled magistrate (and other) judges ever since. Is the
geolocation data that such warrants seek “qualitatively different” from cell-site location information?
Does the precision of geolocation data make requests
for such data comprehensive? Or does that precision
make the requests narrow? Does it matter that the
recipients of geofence warrants typically ask their
customers for permission to store location data? Does
it matter that a geofence warrant begins with no
specific suspect in mind, while a warrant for cell-site
location information does? Judges have found no clear
answers in Carpenter.
Again, amicus takes no position on how the Court
should answer these questions but urges the Court to
answer them. Amicus also respectfully submits that
Carpenter’s dissenting Justices’ predictions have
unfortunately come true in one regard: Carpenter has
“cause[d] confusion” and kept “judges guessing.” Id.
at 333, 340-41 (Kennedy, J., dissenting); see infra Part
II.B. The Court should grant certiorari to dispel that
confusion.
B. Lower Courts Are Hopelessly Divided
Magistrate judges also cannot find the clarity they
require to assess geofence warrants in the lower
courts. As the petition ably describes, circuit courts
and state supreme courts are deeply divided on the
13
constitutional implications of geofence warrants.
Indeed, some have aptly called this area of law “the
Grand Canyon of circuit splits.”10
On one side of the chasm, the Fifth Circuit has held
that geofence warrants (1) do result in searches
and (2) are per se unconstitutional general warrants,
meaning that no amount of probable cause can ever
justify issuing them. See Smith, 110 F.4th at 836-38.
On the other side, a majority of the judges on the
Fourth Circuit has opined that geofence warrants
(1) do not result in searches, and therefore, (2) law
enforcement does not even need probable cause or a
warrant to request geofence location data. See United
States v. Chatrie, 136 F.4th 100, 100 (4th Cir. 2025)
(en banc) (per curiam) (summarily affirming district
court’s application of the good-faith exception to the
motion to suppress), pet. for cert. pending, No. 25-112
(U.S.). Put simply, the Fifth Circuit holds that all
geofence warrants are unconstitutional, while the
Fourth Circuit holds that geofence warrants have no
constitutional implications at all.11
The law is similarly muddled elsewhere. The
Eleventh Circuit, the Georgia Supreme Court, and
the Texas Court of Criminal Appeals have tried to
10 Project for Privacy & Surveillance Accountability, Geofence
Warrants and the Grand Canyon of Circuit Splits (Aug. 20, 2024),
https://perma.cc/NG78-5GHD.
11 While these decisions provide crystal clarity to magistrate
judges in their respective circuits, that clarity does not exist in
other circuits. In addition, the clarity in the Fourth and Fifth
Circuits comes at an unacceptable cost: either the Fifth Circuit
has wrongfully denied federal law enforcement the ability to
use a powerful tool to protect the tens of millions of Americans
living in its jurisdiction, or the Fourth Circuit has wrongfully
denied fundamental Fourth Amendment protections to the tens
of millions of Americans living in its jurisdiction.
14
sail between the extremes by holding that geofence
warrants are not always unconstitutional, but that
they could be in some situations. The Eleventh Circuit reasoned that a “geofence warrant” that “captured
only information within one hundred meters of
specific locations for fifteen to forty minutes” simply
“doesn’t implicate . . . Fourth Amendment concerns.”
United States v. Davis, 109 F.4th 1320, 1330 (11th Cir.
2024), pet. for cert. pending, No. 25-5189 (U.S.). But
it left open the possibility that geofence warrants, if
they cover sufficiently large or nonpublic areas and
timespans, could raise constitutional concerns. See id.
The Georgia Supreme Court similarly rejected
arguments that geofence warrants are per se unconstitutional, holding instead that the particular
warrant before it satisfied the Fourth Amendment’s
probable cause and particularity requirements. It too
left open the possibility that a geofence warrant “not
reasonably calculated to lead . . . to the device held by
the unknown suspect or that suspect’s identity” would
be unconstitutional as “overly broad.” Jones v. State,
913 S.E.2d 700, 710 (Ga. 2025).
The Texas Court of Criminal Appeals likewise
declined to find that geofence warrants are per se
unconstitutional, instead holding that the geofence
warrant before it “supplied ample probable cause” and
“provided sufficient particularity.” App. 19a, 23a. A
hodgepodge of concurring and dissenting opinions
followed, which petitioner has carefully parsed for the
Court. See Pet. 17-19. At base, defendants in Texas
state courts face a different Fourth Amendment
standard than defendants in Texas federal courts face
with similar geofence warrants. See App. 11a-12a.
Put simply, the courts (and even the individual judges
on the courts) are deeply divided. See Appendix (table
summarizing conflicting decisions and opinions).
15
This deep divide provides no meaningful guidance
to lower courts and magistrate judges. Lower courts
continue to reach a wide variety of conclusions. Some
have found geofence warrants to be per se unconstitutional general warrants. See, e.g., United States v.
Fuentes, 2024 WL 5494054, at *10 (Sept. 3, 2024),
report and recommendation adopted, 2025 WL 484628
(Feb. 13, 2025), recon. denied, 2025 WL 1042177 (E.D.
Okla. Apr. 8, 2025). Others have found “that geofence
warrants may be constitutional depending on the
circumstances” and that courts should “analyze
geofence warrants on a case-by-case basis to ensure
they satisfy constitutional requirements.” State v.
Contreras-Sanchez, 5 N.W.3d 151, 163-64 (Minn. Ct.
App. 2024); see also, e.g., United States v. McCracken,
2025 WL 3034953, at *6-10 (E.D. Pa. Oct. 30, 2025).
These persistent disagreements evince the point:
lower courts are too divided to provide meaningful
guidance to magistrate judges not directly bound by a
precedential ruling.
C. Legislation Offers Little Guidance
Magistrate judges cannot look to legislation for
guidance either. Congress and state legislatures have
largely failed to keep pace with changing technology.
No federal statute (and only one state statute)
exists specifically governing the issuance of geofence
warrants.
The leading federal statute concerning third-party
data storage is the Electronic Communications
Privacy Act (“ECPA”). Congress passed the ECPA
in 1986—3 years before Tim Berners-Lee invented
the World Wide Web in 1989,12 12 years before Google
12 See CERN, The birth of the Web, https://perma.cc/NG82HHB6 (last visited Nov. 17, 2025).
16
was incorporated in 1998,13 21 years before Apple
released the first iPhone in 2007,14 and a full 30 years
before the government sought the first geofence
search warrant in 2016.15 It is therefore unsurprising
that the ECPA does not specifically address the procedures the government must follow to obtain geofence
warrants.
Congress has not updated the ECPA to reflect
advances in technology over the past four decades.
And although Congress has provided minor revisions
to the ECPA over the years, including as part of
the Communications Assistance for Law Enforcement
Act (1994) and the USA PATRIOT Act (2001), those
revisions—themselves decades old at this point—do
not squarely address geofence warrants.
State legislatures likewise have provided little
meaningful guidance, much less guidance that
magistrate judges throughout the country can use.
Although an estimated 95% or more of geofence
warrants are approved by state magistrate judges,16
just a handful of States have passed laws governing
the need for warrants to access location data. The
few that have—Maine,17 Minnesota,18 Montana,19
13
See Google, From the garage to the Googleplex,
https://perma.cc/9UZW-2EHQ (last visited Nov. 17, 2025).
14 See Apple, Apple Reinvents the Phone with iPhone (Jan. 9,
2007), https://perma.cc/E5JQ-EH9L.
15 See Owsley, 50 Hofstra L. Rev. at 834.
16 See Google Supplemental Information at 2 (showing that all
“Federal Jurisdictions” accounted for approximately 4-5% of
geofence warrants issued to Google each year from 2018-2020).
17 See Me. Rev. Stat. tit. 16, § 648.
18 See Minn. Stat. § 626A.42(2).
19 See Mont. Code § 46-5-110.
17
New Hampshire,20 Rhode Island,21 Utah,22 and
Vermont23—are notably among the least frequent
issuers of geofence warrants to begin with. See Google
Supplemental Information. And only one of those
States, Utah, has a law specific to geofence warrants.24 These exceptions prove the rule: legislation
concerning geofence warrants is rare, and what little
legislation exists is unhelpful to most magistrate
judges considering applications for geofence warrants.
D. Scholars Are As Divided As The Courts
While legal scholarship is not law, scholarship
can provide guidance to courts. Unfortunately, legal
scholars are as divided as the courts on the question
of geofence warrants. Some have argued, consistent
with Fourth Circuit law, “that a warrant is not
required” at all for “geofence queries.” Reed Sawyers,
For Geofences: An Originalist Approach to the Fourth
Amendment, 29 Geo. Mason L. Rev. 787, 826 (2022).
Others have argued, consistent with Fifth Circuit law,
that “geofence warrants are general warrants and
should be unconstitutional per se.” Note, Geofence
Warrants and the Fourth Amendment, 134 Harv. L.
Rev. 2508, 2511, 2515-20 (2021); see also Haley
Amster & Brett Diehl, Note, Against Geofences, 74
Stan. L. Rev. 385, 393 (2022) (“[G]eofence warrants
are unconstitutional general warrants because of
the discretion given to law-enforcement officers in
warrant execution.”). Still others simply note “that
geofences may be searches” requiring further Fourth
20 See N.H. Rev. Stat. § 644-A:2.
21 See 12 R.I. Gen. Laws § 32-2.
22 See Utah Code §§ 77-23c-102, 77-23f-102.
23 See Vt. Stat. tit. 13, §§ 8101(8), 8102.
24 See Utah Code § 77-23f-102.
18
Amendment scrutiny, even if “most geofences will not
be searches” (at least in that author’s view). Jordan
Wallace-Wolf, Unfenced: The Fourth Circuit Gives
Geofencing Its First Appellate Go-Ahead in United
States v. Chatrie, 82 Wash. & Lee L. Rev. Online 1,
8-9 (2024) (emphasis added).
In sum, this Court should grant review because
judicial precedent, legislation, and scholarship alike
provide no meaningful source of guidance for magistrate judges.
III. ONLY THIS COURT CAN PROVIDE THE
GUIDANCE MAGISTRATE JUDGES NEED
A. Permitting Further Percolation Is Futile
This Court often allows difficult issues to “percolate”
in the lower courts before weighing in. But it should
not “wait to decide” a constitutional question where
“further percolation is of little value.” Snope v. Brown,
145 S. Ct. 1534, 1538 (2025) (Thomas, J., dissenting
from the denial of certiorari). Here, percolation is of
no value.
As explained supra Part II.B, every idea that can be
aired has been aired. The variety and breadth of
thoughtful opinions analyzing the Fourth Amendment
implications of geofence warrants leave the Court
well-positioned to analyze the questions presented.
Further percolation will not break new ground or add
incremental value.
Nor will further percolation allow the circuit split
here to resolve itself. The split is clear, with the
Fourth and Fifth Circuits at each end of the spectrum;
the Eleventh Circuit, the Georgia Supreme Court, and
the Texas Court of Criminal Appeals in the middle;
and several courts at the federal and state levels
generating multiple concurring opinions and separate
writings. See supra Part II.B. No reason exists to
19
think that, with more time, courts around the country
will coalesce around a majority position. Quite the
opposite, to borrow from Judge Newell’s opinion
below, there is “an obvious and insurmountable
deadlock,” and the lower courts “simply can’t do any
better.” App. 100a-101a (Newell, J., concurring in
denial of rehearing).
B. Legislatures Cannot Provide The Needed
Guidance
This Court should not wait for Congress or state
legislatures to come to the rescue for two reasons.
First, no reason exists to believe that Congress or
state legislatures will pass laws governing geofence
warrants any time soon. “Congress has not indicated
a willingness to regulate law enforcement’s access to
geofence data.” Amster & Diehl, 74 Stan. L. Rev.
at 438. Indeed, a recent report by the Congressional
Research Service analyzing the current state of the
law surrounding geofence warrants suggests that,
although “Congress could amend the [Stored Communications Act] to affect protections for location history
information,” Congress may instead “leave resolution
of the legality of geofence warrants to the courts.”
Peter G. Berris & Clay Wild, Cong. Rsch. Serv.,
Geofence Warrants: A Circuit Split on Application of
the Fourth Amendment 5 (Feb. 27, 2025) (“Berris &
Wild, Geofence Warrants”).
States likewise have not indicated a widespread
willingness to regulate law enforcement’s access to
geofence data. Utah alone has a law on the books
specifically governing geofence warrants. See supra
Part II.C. A group of New York legislators has been
trying without success for the past five years to pass
legislation that would ban law enforcement from
using geofence searches entirely. See Amster & Diehl,
20
74 Stan. L. Rev. at 439 (discussing failed efforts in
2020); S.B. S404, 2025-2026 Legis. Reg. Sess. (N.Y.
Jan. 8, 2025) (the most recent iteration of that effort).
Amicus is aware of no other State even attempting to
pass such a law governing geofence warrants.
Second, even if Congress and the States were
inclined to pass laws governing geofence warrants,
those laws may not answer the fundamental Fourth
Amendment questions that magistrate judges need
answered. Congress and the States could “exceed
[their] authority in instructing the courts on how to
interpret the Fourth Amendment” in this context.
Berris & Wild, Geofence Warrants at 4. That is
because there is a “constitutional floor below which
Fourth Amendment rights may not descend,” Carpenter, 585 U.S. at 403 (Gorsuch, J., dissenting), and the
political branches do not always regulate consistent
with that floor.
Carpenter itself illustrates the point. The Stored
Communications Act provided standards and procedures that Congress deemed sufficient to govern
access to and use of cell-site location information
from third parties. The Carpenter majority, however,
determined that those standards and procedures fell
below the Fourth Amendment floor, finding that a
search occurred and that that search was unlawful
despite having complied with the statutory requirements Congress dictated. Id. at 316-18 (majority).
Here, that same risk exists, particularly where the
currently muddled judicial precedent is unlikely to
offer legislators clear guideposts.
For this reason, this Court should not wait for
legislatures to act.
21
C. This Court Must Provide The Needed
Guidance
Because neither lower courts nor legislatures
can provide the clarity magistrate judges need to
safeguard Fourth Amendment protections, only this
Court can provide much-needed guidance. On the one
hand, geofence warrants provide “law enforcement a
powerful new tool to carry out its important responsibilities.” Carpenter, 585 U.S. at 320. On the other,
geofence warrants threaten to expose detailed location
data for untold numbers of innocent persons to the
government. In Texas alone, more than 31 million
people now live under a regime in which their constitutional rights change based on which courthouse
they enter.
Magistrate judges should not be left to balance these
interests on an ad hoc basis without clear guideposts.
Indeed, this Court has recognized as much: “[T]he
Court is obligated—as subtler and more far-reaching
means of invading privacy have become available to
the Government—to ensure that the progress of science
does not erode Fourth Amendment protections.” Id.
(cleaned up).
CONCLUSION
The petition for a writ of certiorari should be
granted.
22
Respectfully submitted,
ALEJANDRA ÁVILA
Counsel of Record
MATTHEW J. WILKINS
NOELLE SUAREZ-MURIAS*
SPENCER R. LOCKWOOD**
KELLOGG, HANSEN, TODD,
FIGEL & FREDERICK, P.L.L.C.
1615 M Street, N.W., Suite 400
Washington, D.C. 20036
(202) 326-7900
(aavila@kellogghansen.com)
November 19, 2025
* Admitted to practice only in Illinois;
work supervised by members of the Firm
** Admitted to practice only in Texas;
work supervised by members of the Firm
APPENDIX
1a
The following tables summarize the diverse positions that courts (and individual judges within those
courts) have taken on the question presented here:
Wells v. State (TX)
Opinion
Summary
Majority
Assuming without deciding that
search occurred, warrant supported
by probable cause
Finley, J.,
concurring
Geofence is not a search
Data is voluntarily shared
Newell, J.,
concurring
Not a search at Step One or
Step Two
Search at Step Three
State v. Jones (GA)
Opinion
Summary
Majority
Assuming without deciding that
search occurred, warrant satisfied
particularity requirement
United States v. Smith (5th Cir.)
Opinion
Summary
Majority
Geofence is a search
Geofence warrants are per se unconstitutional general warrants
United States v. Davis (11th Cir.)
Opinion
Summary
Majority
Geofence warrants do not implicate
Fourth Amendment privacy concerns,
at least when limited in time and
area and to public spaces
2a
United States v. Chatrie (4th Cir.)
Opinion
Summary
Diaz, C.J.,
concurring
Without addressing the constitutional question, good-faith exception applies
Wilkinson, J.,
concurring
Geofence is not a search
Data is voluntarily shared
Categorical bar is not appropriate
Niemeyer, J.,
concurring
Geofence is not a search
Data is like fingerprints, voluntarily left behind
King, J.,
concurring
Geofence is not a search
Good-faith exception applies
Wynn, J.,
concurring in
judgment
Geofence is a search
Third-party doctrine is not appropriate given the data requested
Richardson, J.,
concurring
Geofence is not a search
Data was voluntarily disclosed
Heytens, J.,
concurring
Good-faith exception applies because
geofence landscape is too ambiguous
to blame officers
Berner, J.,
concurring
Geofence is a search when nonanonymous location history data is
collected
Step One is not categorically overbroad
Steps Two and Three are searches
Gregory, J.,
dissenting
Geofence is a search
Good-faith exception applies
This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.