The Bill of Rights Series
Amendment IV: The Government Must Build Its Own Case
Part 4 of a 10-part series examining the Bill of Rights — and the federal record of violating it.
The Fourth Amendment was written by people who had lived under general warrants. They knew exactly what they were prohibiting.
“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.”
British writs of assistance were open-ended authorizations — no specific location, no specific target, no specific items. An officer holding one could search anywhere, seize anything, and answer to no one. The Framers had English court decisions striking down similar instruments in front of them when they wrote the amendment. The requirement of particularity — this place, this person, these items — was the direct answer to the general warrant’s open-ended power.
The government may not conduct a fishing expedition and sort through the catch afterward looking for evidence of something.
What the Government Built Instead
The exclusionary rule — evidence obtained in violation of the Fourth Amendment cannot be used in court — was established in Weeks v. United States (1914) and extended to the states in Mapp v. Ohio (1961). The rule exists because a prohibition with no consequence is not a prohibition. If illegally obtained evidence is usable, the incentive to obtain it legally disappears.
Katz v. United States (1967) held that the amendment protects people, not just places — warrantless electronic eavesdropping on a public phone booth violated the Fourth Amendment because the person using it had a reasonable expectation of privacy in the conversation. The government cannot evade the warrant requirement simply by conducting surveillance without physical entry.
Each of those decisions closed a gap. What followed was a sustained effort to find new ones.
The Foreign Intelligence Surveillance Act of 1978 created a specialized court to oversee foreign intelligence collection. The FISA Court operates in secret, hears only the government’s side, and approves the overwhelming majority of requests it receives. Whether this constitutes meaningful judicial oversight or the institutional appearance of it is a question the public is structurally prevented from answering, because the court’s work is classified.
After September 11, the PATRIOT Act expanded surveillance authorities substantially. Section 215 was used to collect the phone metadata of virtually every American — not as part of a targeted investigation but as a standing program. The government’s position was that collecting data on everyone was not a search of anyone in particular. That position rested on the third-party doctrine: information voluntarily shared with a third party carries no Fourth Amendment protection.
The third-party doctrine made sense when the information at issue was a bank deposit slip. It fits less cleanly when the third party holds a continuous record of every location visited, every call made, every search conducted, and every person communicated with. Sharing data with a phone company to make a call is not obviously the same kind of voluntary disclosure as writing a check.
What the Courts Have Said
Carpenter v. United States (2018) held that the government generally needs a warrant to obtain historical cell-site location data. The Court recognized that such records provide a comprehensive account of a person’s movements and associations that has no analog in pre-digital surveillance. The third-party doctrine does not automatically apply when the information is this detailed and this continuous.
Riley v. California (2014) required a warrant to search a cell phone seized incident to arrest. The government argued the search fell within the existing exception for items on an arrested person. The Court’s response was that a cell phone is not a cigarette pack. The exception exists to protect officer safety and prevent evidence destruction — neither purpose is served by searching the phone after the arrest is complete.
United States v. Jones (2012) held that attaching a GPS device to a vehicle without a warrant constituted a search. Sustained, comprehensive tracking of a person’s location is qualitatively different from observing a single public trip.
Each decision drew a line. What lies beyond each line — bulk collection under national security authority, algorithmic analysis of lawfully obtained data, compelled decryption of devices — remains contested.
The Fifth Amendment Connection
The Fourth and Fifth Amendments protect the same structural principle from different directions. The Fourth limits how the government may gather evidence. The Fifth limits its ability to force a person to supply it — “nor shall any person be compelled in any criminal case to be a witness against himself.” Together they encode one requirement: the government must build its case through independent investigation, not by ransacking private spaces or compelling the accused to do the work for them.
Miranda v. Arizona (1966) sits at their intersection. An arrest is a Fourth Amendment seizure. Custodial interrogation following that seizure is where the Fifth becomes critical. The warnings Miranda requires exist because the coercive conditions of custody make the voluntariness of any statement suspect without them.
The same intersection appears in compelled decryption. Searching a phone engages the Fourth Amendment. Demanding the passcode raises the Fifth — a passcode is not a physical object. It is knowledge inside a person’s mind. Compelling its disclosure compels testimony. Courts have not settled where that line falls.
The Pattern
General warrants allowed officers to search everywhere and seize everything. The Fourth Amendment prohibited them by name. The government then developed surveillance tools that collect everything without entering a physical space and argued that constitutional rules written for physical searches do not apply.
This is not a claim that modern technology has outpaced the amendment’s letter. It is a claim that the letter — written for papers in a desk drawer — does not reach data on a server. The Framers were concerned with general warrants because they destroyed the security of correspondence and the privacy of the home. Surveillance that produces a more complete picture of a person’s life than any physical search ever could raises the same concern. The amendment protects persons, houses, papers, and effects. It does not protect only the physical versions of those things.
The warrant requirement is not a bureaucratic obstacle. It is the mechanism by which an independent judge — not the investigating officer — determines whether probable cause exists before the search occurs. A government that searches first and seeks approval later, or that collects data on everyone and queries it when a target is identified, has inverted that sequence. The argument that national security requires faster, broader access is the same argument British officials made for writs of assistance. The Constitution reflects the Founders’ answer.
Next: The Fifth Amendment — due process, self-incrimination, and what “nor shall private property be taken for public use, without just compensation” means when the government wants what you own.
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