In the United States, law enforcement’s use of geofence warrants—court orders compelling tech companies to provide location data for all devices within a specified area and timeframe—is among the most contentious digital civil liberties issues of our time. Federal courts have struggled to apply existing Fourth Amendment doctrine to such searches, and in the meanwhile, a three-step procedure developed by Google—currently the main purveyor of location data to law enforcement—has been doing most of the work that the law should be doing in channeling how law enforcement agencies conduct searches of geolocation databases.
We believe that this situation is untenable, and that geofence searches should be regulated by statutory law. Since most crimes are state offenses and are investigated by state and local law enforcement, we believe that state legislatures should step up to improve the manner in which such searches are conducted. Accordingly, the Samuelson-Glushko Technology Law and Policy Clinic at the University of Colorado Law School has developed a comprehensive model policy framework that states can adopt to regulate these powerful but invasive investigative tools. We have done so at the request of the Center for Democracy and Technology (CDT), although the policy we have developed reflects the thinking of our clinic team, rather than the position of CDT, on this issue.
Geofence warrants represent a fundamental shift in how criminal investigations are conducted. Unlike traditional warrants targeting specific suspects, these “reverse-location warrants” cast a digital dragnet, capturing location data from every device within designated boundaries. When a bank robbery occurs, for instance, law enforcement might request data for all devices within a 150-meter radius during the hour surrounding the crime—potentially sweeping up information about hundreds of innocent bystanders.
"If it was easy, everybody would be doing it. It isn't, and they don't." —Me
"Life is not a matter of holding good cards, but of playing a poor hand well." –Josh Billings (pseudonym of Henry Wheeler Shaw), Josh Billings on Ice, and Other Things (1868) (erroneously attributed to Robert Louis Stevenson, among others)
“I am still learning.” —Domenico Giuntalodi (but misattributed to Michelangelo Buonarroti (common phrase throughout 1500's)).
"Love work; hate mastery over others; and avoid intimacy with the government."
—Shemaya, in the Thalmud
"It is a pleasant world we live in, sir, a very pleasant world. There are bad people in it, Mr. Richard, but if there were no bad people, there would be no good lawyers."
—Charles Dickens, “The Old Curiosity Shop ... With a Frontispiece. From a Painting by Geo. Cattermole, Etc.” 255 (1848)
"A system of law that not only makes certain conduct criminal, but also lays down rules for the conduct of the authorities, often becomes complex in its application to individual cases, and will from time to time produce imperfect results, especially if one's attention is confined to the particular case at bar. Some criminals do go free because of the necessity of keeping government and its servants in their place. That is one of the costs of having and enforcing a Bill of Rights. This country is built on the assumption that the cost is worth paying, and that in the long run we are all both freer and safer if the Constitution is strictly enforced."
—Williams
v. Nix, 700 F. 2d 1164, 1173 (8th Cir. 1983) (Richard Sheppard Arnold,
J.), rev'd Nix v. Williams, 467 US. 431 (1984).
"The criminal goes free, if he must, but it is the law that sets him free. Nothing can destroy a government more quickly than its failure to observe its own laws,
or worse, its disregard of the charter of its own existence." —Mapp
v. Ohio, 367 U.S. 643, 659 (1961).
"Any costs the exclusionary rule are costs imposed directly by the Fourth Amendment."
—Yale Kamisar, 86 Mich.L.Rev. 1, 36 n. 151 (1987).
"There have been powerful hydraulic pressures throughout our history that
bear heavily on the Court to water down constitutional guarantees and give the
police the upper hand. That hydraulic pressure has probably never been greater
than it is today."
— Terry
v. Ohio, 392 U.S. 1, 39 (1968) (Douglas, J., dissenting).
"The great end, for which men entered into society, was to secure their
property."
—Entick
v. Carrington, 19 How.St.Tr. 1029, 1066, 95 Eng. Rep. 807 (C.P. 1765)
"It is a fair summary of history to say that the safeguards of liberty have
frequently been forged in controversies involving not very nice people. And
so, while we are concerned here with a shabby defrauder, we must deal with his
case in the context of what are really the great themes expressed by the Fourth
Amendment."
—United
States v. Rabinowitz, 339 U.S. 56, 69 (1950) (Frankfurter, J., dissenting)
"The course of true law pertaining to searches and seizures, as enunciated
here, has not–to put it mildly–run smooth."
—Chapman
v. United States, 365 U.S. 610, 618 (1961) (Frankfurter, J., concurring).
"A search is a search, even if it happens to disclose nothing but the
bottom of a turntable."
—Arizona
v. Hicks, 480 U.S. 321, 325 (1987)
"For the Fourth Amendment protects people, not places. What a person knowingly
exposes to the public, even in his own home or office, is not a subject of Fourth
Amendment protection. ... But what he seeks to preserve as private, even in
an area accessible to the public, may be constitutionally protected."
—Katz
v. United States, 389 U.S. 347, 351 (1967)
“Experience should teach us to be most on guard to
protect liberty when the Government’s purposes are beneficent. Men born
to freedom are naturally alert to repel invasion of their liberty by evil-minded
rulers. The greatest dangers to liberty lurk in insidious encroachment by men
of zeal, well-meaning but without understanding.”
—United
States v. Olmstead, 277 U.S. 438, 479 (1925) (Brandeis, J., dissenting)
“Liberty—the freedom from unwarranted
intrusion by government—is as easily lost through insistent nibbles by
government officials who seek to do their jobs too well as by those whose purpose
it is to oppress; the piranha can be as deadly as the shark.”
—United
States v. $124,570, 873 F.2d 1240, 1246 (9th Cir. 1989)
"You can't always get what you want / But if you try sometimes / You just might find / You get what you need." —Mick Jagger & Keith Richards, Let it Bleed (album, 1969)
"In Germany, they first came for the communists,
and I didn't speak up because I wasn't a communist. Then they came for the Jews,
and I didn't speak up because I wasn't a Jew. Then they came for the trade unionists,
and I didn't speak up because I wasn't a trade unionist. Then they came for
the Catholics and I didn't speak up because I wasn't a Catholic. Then they came
for me–and by that time there was nobody left to speak up."
—Martin Niemöller (1945) [he served seven years in a concentration
camp]
“You know, most men would get discouraged by now. Fortunately for you, I am not most men!” ---Pepé Le Pew
"The point of the Fourth Amendment, which often is not grasped by zealous officers, is not that it denies law enforcement the support of the usual inferences which reasonable men draw from evidence. Its protection consists in requiring that those inferences be drawn by a neutral and detached magistrate instead of being judged by the officer engaged in the often competitive enterprise of ferreting out crime." —Johnson v. United States, 333 U.S. 10, 13-14 (1948)
The book was dedicated in the first (1982) and sixth (2025) editions to Justin William Hall (1975-2025). He was three when this project started in 1978.
