The Fight Against Reverse Location Warrants: Why the Ninth Circuit Must Declare Tower Dumps Unconstitutional
On November 4th, the Electronic Frontier Foundation (EFF) and the American Civil Liberties Union (ACLU) filed an amicus brief in the Ninth Circuit’s United States v. Spurlock case, arguing that tower‑dump warrants are a modern incarnation of the dreaded general warrant and that the court must hold them categorically unconstitutional. source↗ This move follows the Supreme Court’s recent decision striking down geofence warrants, a similar technique that allows police to harvest location data for every cell phone in a specified area. source↗ The Ninth Circuit’s review could set a nationwide precedent, reinforcing the Fourth Amendment’s protection against untargeted, mass surveillance.
What Is a Tower Dump?
A tower dump, also known as a reverse location warrant, compels cellular providers to produce the location histories of every device connected to a particular cell tower at a given time. In practice, this means that a single warrant can surface the movements of thousands or even millions of innocent bystanders, all without any showing of probable cause or particularized suspicion. The Spurlock investigation, which prompted the warrant, began with two murder victims found on a remote stretch of California’s Highway 33. Police also discovered a car belonging to one of the victims several miles away on the same road, and they quickly requested a tower dump covering the entire corridor. The warrant ultimately produced location data on nearly 1,700 unique phones. source↗ Such sweeping data collection is a textbook example of a general warrant—an unconstitutional tool that the framers explicitly sought to ban.
Supreme Court Sets the Stage
The Supreme Court’s recent decision in Chatrie v. United States held that geofence warrants, which similarly require providers to hand over data for every device within a defined geographic boundary, are unconstitutional searches under the Fourth Amendment. The Court underscored that the framers required surveillance to be limited in scope, duration, and notice, and that mass data collection without probable cause violates those limits. source↗ The Spurlock brief argues that tower dumps are essentially the same reverse‑location technology, merely an older variant, and therefore must be treated with the same constitutional gravity.
The Ninth Circuit’s Mixed Signal
District Judge Michael Klein, in a 2025 ruling, relied on a Fifth Circuit decision that deemed geofence warrants unconstitutional to conclude that tower dumps are similarly invalid general warrants. However, the judge refused to suppress the evidence obtained through the warrant, citing the good‑faith doctrine—a principle that protects law‑enforcement officers who act in good faith under existing statutes. The brief contends that applying the good‑faith doctrine here would let police continue to use a tool that the Supreme Court has already declared a violation of the Fourth Amendment. source↗ The Ninth Circuit’s decision therefore stands in direct conflict with the Supreme Court’s clear guidance.
Why the Good‑Faith Doctrine Is a Bad Fit
The good‑faith doctrine is traditionally a narrow shield, protecting officers who unknowingly misapply a law that is later deemed invalid. In the Spurlock case, the Supreme Court’s geofence decision shows that the warrant itself is unlawful even at the time it was issued. Because the warrant was unconstitutional from the outset, there is no bona fide good faith to defend. The brief argues that allowing the Ninth Circuit to apply the doctrine would create a perverse incentive for police to keep filing reverse‑location warrants, knowing that courts will likely refuse to suppress the data. source↗ In other words, the doctrine would be used to shield attorneys from the very constitutional violation the Supreme Court has already condemned.
The Privacy Toll on Innocent Bystanders
Every cell phone that is handed over to the authorities through a tower dump shares its location history with the police, regardless of whether the owner has any connection to a crime. That data can reveal intimate details—where a person dined, who they spoke to, or even their private movements at home—everything that the Fourth Amendment protects. By pummeling the entire area with a blanket warrant, law‑enforcement agencies effectively cast a net over an entire community, violating the basic principle that a warrant must be specific and tailored to a particular individual. The brief cites that the Supreme Court’s geofence ruling emphasized that mass surveillance without probable cause is a violation of privacy expectations that were enshrined in the Fourth Amendment from the beginning. source↗ The Ninth Circuit’s refusal to suppress data sets a dangerous precedent: it normalizes the notion that the state can keep a permanent, unfiltered record of everyone’s movements.
Technological Distinctions Are Irrelevant to Constitutional Law
Some defenders of tower dumps argue that the technology is older than geofence warrants and therefore deserves a different legal treatment. The brief counters that constitutional principles do not hinge on the age of a technique; rather they hinge on the effect of that technique on individual liberties. Both reverse‑location and geofence warrants produce the same end result: vast, untargeted data sweeps that violate the Fourth Amendment’s limits on scope, notice, and probable cause. The framers did not distinguish between “old” and “new” surveillance tools; they demanded that every search be narrowly tailored. source↗ Thus, the Ninth Circuit must treat tower dumps with the same severity the Supreme Court applied to geofence warrants.
Implications for the Nation’s Surveillance Landscape
Should the Ninth Circuit ultimately refuse to hold tower dumps unconstitutional, the ripple effect would be felt across all federal, state, and local jurisdictions. Police departments that rely on the good‑faith doctrine could continue to file blanket warrants, expanding their surveillance reach and eroding public trust. Conversely, a ruling that categorically deems tower dumps unconstitutional would reaffirm the Fourth Amendment’s role as a bulwark against mass surveillance, giving law‑enforcement agencies a clear legal boundary to respect. The brief underscores that a definitive ruling would eliminate the ambiguity that currently leaves prosecutors free to interpret “widely applicable” warrants in ways that favor state power over individual rights. source↗ It would also send a strong message that the judiciary will not entertain blanket data sweeps under the guise of good faith.
A Call for Constitutional Clarity
Disruptarian analysis insists that the Ninth Circuit has a duty to align its decision with the Supreme Court’s recent ruling and the Fourth Amendment’s original intent. By refusing to suppress tower‑dump data under the good‑faith doctrine, the court would effectively endorse a tool that bypasses the core protections against general warrants. The Amicus brief argues that the only defensible outcome is a categorical declaration of unconstitutionality, which would protect innocent bystanders and preserve the balance between law‑enforcement needs and civil liberties. The legal community must recognize that the framers envisioned a society in which the state could not simply turn a dial and track every citizen. The Ninth Circuit’s decision will either uphold that vision or erode it further.
Conclusion: A Crucial Moment for Privacy Rights
United States v. Spurlock is not just a case about a single murder investigation; it is a battlefield for the Fourth Amendment’s core principle that law‑enforcement must be held to a high standard of specificity and probable cause. The Ninth Circuit’s ruling will either reinforce the constitutional limits on mass surveillance or open the floodgates for unchecked data collection. For those who believe that freedom and privacy are inseparable, the court’s decision is a litmus test of its commitment to protecting citizens from the modern equivalent of a general warrant. The EFF and ACLU’s brief is a clarion call: the state must not be allowed to treat the entire populace as a suspect simply because they are within a geographic boundary.
In the end, the Ninth Circuit has a choice: uphold the Supreme Court’s guidance and strike down tower dumps as unconstitutional, or continue a dangerous precedent that places institutional power above the individual’s right to privacy. The stakes are high, and the choice will echo across the nation for years to come. Disruptarians stand ready to watch, to demand accountability, and to champion the liberties that the Fourth Amendment was designed to protect. If the court takes the right path, it will send a clear message that the state can no longer wield reverse‑location warrants as a blanket tool of surveillance.
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