Recent Fourth Amendment violation cases from the Supreme Court and federal appellate courts have reshaped what counts as an unreasonable search or seizure, extending protection into cell phone data and location history, barring police from treating welfare checks and minor-offense pursuits as free passes into the home, and recognizing that a bullet can be a seizure even when the person shot gets away. The decisions below are the ones that changed the law or exposed a sharp split in how courts apply it.
Caniglia v. Strom (2021): No “Community Caretaking” Entry Into Homes
Officers responded to a welfare check on Edward Caniglia after a domestic argument and persuaded him to go to the hospital for a psychiatric evaluation. While he was gone, without his consent and without a warrant, they entered his home and took two handguns.1Justia U.S. Supreme Court Center. Caniglia v. Strom, 593 US (2021)
Lower courts had green-lit the entry under the “community caretaking” exception, a doctrine first recognized for non-investigative work like helping stranded motorists. A unanimous Supreme Court rejected the extension. Justice Thomas wrote that the right to retreat into your own home and be free from unreasonable intrusion sits at the core of the Fourth Amendment, and nothing about roadside caretaking opens the door to warrantless home entries whenever officers believe they are helping.1Justia U.S. Supreme Court Center. Caniglia v. Strom, 593 US (2021) After Caniglia, a welfare check still requires a warrant or a genuine emergency before officers can cross the threshold.
Lange v. California (2021): Hot Pursuit of a Misdemeanor Is Not Automatic
A California highway patrol officer saw Arthur Lange playing loud music and honking while driving. The officer activated his lights, but Lange drove the short distance to his driveway and pulled into his garage. The officer followed on foot, stuck his foot under the closing garage door, and conducted field sobriety tests inside.2Justia U.S. Supreme Court Center. Lange v. California, 594 US (2021)
Several lower courts had treated any hot pursuit as an automatic exception to the warrant requirement. The Supreme Court said no. Justice Kagan’s opinion held that pursuing a misdemeanor suspect does not, by itself, justify a warrantless entry into the home. Officers must point to a real emergency, such as evidence being destroyed or an immediate threat to safety, before they can force their way in over a low-level offense.2Justia U.S. Supreme Court Center. Lange v. California, 594 US (2021) Each misdemeanor pursuit now gets evaluated on its own facts.
Torres v. Madrid (2021): Shooting Someone Is a Seizure
New Mexico State Police officers arrived at an apartment complex at dawn to execute an arrest warrant on a different person. They approached Roxanne Torres, who was standing near a vehicle, and quickly determined she was not their target. Torres got into her car and began to drive away. Two officers fired at her, striking her twice in the back. She escaped and drove to a hospital in another city.3Justia U.S. Supreme Court Center. Torres v. Madrid, 592 US (2021)
The lower courts had held that no seizure occurred because Torres was never actually stopped. The Supreme Court reversed. Chief Justice Roberts, writing for the majority, held that applying physical force to a person’s body with intent to restrain is itself a seizure, whether or not the person submits. A bullet accomplishes the same corporal touching as a hand on the shoulder during an arrest.3Justia U.S. Supreme Court Center. Torres v. Madrid, 592 US (2021) Without that ruling, the Fourth Amendment would not have applied at all, and Torres would have had no constitutional claim to pursue.
Barnes v. Felix (2025): The “Moment of Threat” Rule Is Dead
Building on Torres, the Court in 2025 addressed how judges should evaluate whether an officer’s use of force was reasonable. Some lower courts had adopted a “moment-of-threat” rule, which looked only at the instant force was applied and ignored everything leading up to it.
The Court rejected that framing. Reasonableness has to be judged on the totality of the circumstances, and a court “cannot review the totality of the circumstances if it has put on chronological blinders.”4Supreme Court of the United States. Barnes v. Felix (2025) An officer who recklessly escalated a situation can no longer escape scrutiny by pointing to the dangerous second at the end. The lead-up is now part of the analysis.
Carpenter v. United States (2018): Cell-Site Location Data Needs a Warrant
Law enforcement obtained 127 days of historical cell-site location information from Timothy Carpenter’s wireless carriers, cataloging nearly 13,000 location points, without a search warrant. The data placed Carpenter near several robbery locations and was used to convict him.5Justia U.S. Supreme Court Center. Carpenter v. United States, 585 US (2018)
The Court held that acquiring that volume of location history is a search under the Fourth Amendment and generally requires a warrant backed by probable cause. The ruling cut into the long-standing “third-party doctrine,” which had said you lose privacy expectations in information voluntarily shared with a business. Cell-site records create such a detailed picture of a person’s movements, associations, and habits that they warrant protection even when stored by a carrier.6Supreme Court of the United States. Carpenter v. United States (2018)
A common misreading: the Court did not set a specific day threshold below which police can grab location data warrant-free. The majority declined to draw a numerical line, saying only that 127 days was “a far cry from the limited quantum of information” that might require different treatment. Real-time tracking, tower dumps, and other categories of records were left for later cases.5Justia U.S. Supreme Court Center. Carpenter v. United States, 585 US (2018)
The Geofence Warrant Split
Geofence warrants invert the normal search model. Instead of naming a suspect and seeking evidence, law enforcement defines a geographic area and time window and asks a company, usually Google, to identify every device that was present. Courts are now openly divided over whether the technique can survive the Fourth Amendment.
In 2024, the Fifth Circuit held that geofence warrants are “general warrants categorically prohibited by the Fourth Amendment.”7United States Court of Appeals for the Fifth Circuit. Geofence Warrant Opinion (2024) The court compared them to telling officers to search every house on a city block because a crime happened somewhere nearby, which is precisely what the Framers wrote the Fourth Amendment to prevent.
The Fourth Circuit went the other way in United States v. Chatrie (2024), finding that Google’s location history data wasn’t revealing enough to trigger Fourth Amendment protections at all. Google announced in 2023 that it would begin storing location data locally on users’ devices and shortening default retention, a shift that may reduce the practical reach of these warrants regardless of how courts rule.8Congressional Research Service. Geofence Warrants and the Fourth Amendment The circuit split is a strong candidate for eventual Supreme Court review.
Vehicles and Blood: Where Recent Cases Did Not Find a Violation
Not every recent challenge has produced a win for defendants, and the losses define the current boundary just as sharply as the wins.
Mitchell v. Wisconsin (2019) addressed warrantless blood draws from unconscious drunk-driving suspects. Gerald Mitchell was arrested on suspicion of intoxicated driving but was too incapacitated by the time he reached the station to provide a breath sample. Officers took him to a hospital for a blood draw. A Supreme Court plurality concluded that when a driver is unconscious and cannot take a breath test, the natural dissipation of alcohol in the bloodstream generally creates enough urgency to permit a warrantless draw.9Justia U.S. Supreme Court Center. Mitchell v. Wisconsin, 588 US (2019) The word “generally” matters. Because the ruling came from a four-justice plurality rather than a full majority, defendants can still argue that the specific facts of their case didn’t justify skipping the warrant.
Arizona v. Gant (2009), while older, still controls vehicle searches incident to arrest and continues to drive suppression rulings. Officers can search the passenger compartment only if the arrested person could still reach into the vehicle at the time of the search, or if it’s reasonable to believe the vehicle contains evidence of the crime that led to the arrest.10Justia U.S. Supreme Court Center. Arizona v. Gant, 556 US 332 (2009) Once a suspect is handcuffed in a patrol car, the officer-safety rationale for rummaging through the vehicle evaporates, and for arrests that wouldn’t logically produce physical evidence, the evidentiary rationale is gone too.
What Happens When a Court Finds a Violation
A ruling that a search or seizure violated the Fourth Amendment produces two possible remedies, and both have narrowed in recent years.
In a criminal case, the exclusionary rule generally keeps unlawfully obtained evidence out of trial, along with any “fruit of the poisonous tree” discovered because of the initial illegality. The rule has grown-in exceptions that prosecutors use aggressively. Evidence stays in when officers can show an independent source, when discovery was inevitable through normal investigation, or when officers acted in good-faith reliance on a warrant, statute, or precedent later found defective. The good-faith exception in particular has expanded to cover faulty database records and warrants with technical defects, which is why winning a suppression motion is harder than many defendants expect.
On the civil side, the main vehicle for suing state and local officers is 42 U.S.C. ยง 1983, which allows damages suits against government actors who deprive you of constitutional rights.11Office of the Law Revision Counsel. 42 USC 1983 – Civil Action for Deprivation of Rights Qualified immunity is the standard obstacle: officers avoid personal liability unless the right they violated was “clearly established” by prior case law involving similar facts. Courts resolve the question early, often before any evidence-gathering, which keeps many meritorious claims from ever reaching a jury.
Suing a federal officer is harder still. The Supreme Court recognized a Fourth Amendment damages action against federal agents in Bivens v. Six Unknown Named Agents (1971), then spent decades narrowing it. In Egbert v. Boule (2022), the Court refused to extend Bivens to a claim against a Border Patrol agent who allegedly used excessive force by shoving an inn owner to the ground, holding that federal courts should almost never create new damages actions against federal officers when Congress has not authorized one.12Justia U.S. Supreme Court Center. Egbert v. Boule, 596 US (2022) Unless the facts closely mirror the original 1971 Bivens scenario of a warrantless home search by narcotics agents, a federal court will almost certainly decline the case. That gap leaves many victims of federal misconduct without a practical damages remedy even where a clear Fourth Amendment violation occurred.13Constitution Annotated. Fourth Amendment