Key Takeaways
- Under Whren v. United States, a traffic stop backed by probable cause is reasonable under the Fourth Amendment even if the officer's real motive was something else.
- The Supreme Court also allows full custodial arrests for minor offenses, such as a seatbelt violation, when officers have probable cause.
- Claims of racially selective enforcement are analyzed under the Equal Protection Clause rather than the Fourth Amendment, and some states and cities have separately limited stops for minor violations.
Picture a highway where nearly everyone is speeding. If an officer pulls over one young Black driver going 63 in a 55 while other cars pass at 72 or 75, does the officer's reason for choosing that driver matter under the Constitution?
In this TalksOnLaw Brief, Daniel Capra, the Philip D. Reed Professor of Law at Fordham Law School and a nationally recognized expert on evidence and criminal procedure, explains why the Supreme Court has said that, for Fourth Amendment purposes, it does not. He walks through the reasoning behind the rule on so-called pretextual stops and what it allows officers to do once a stop is made.
Why the Officer's Motive Does Not Count
Professor Capra explains that in Whren v. United States, a unanimous 9-0 decision, the Supreme Court held that the Fourth Amendment does not look at the subjective motivations of police officers. The question is objective: did the officer have probable cause to arrest, or reasonable suspicion to stop? In his highway example, the driver was speeding, so there was probable cause to pull him over. The fact that other drivers were going faster is not a relevant point. Even if the officer, in his heart of hearts, chose the driver for a racially selective reason, Professor Capra says that motive does not change the analysis.
From a Ticket to a Full Arrest
The stakes grow, he notes, because many jurisdictions allow an arrest for a traffic violation. Once the driver is arrested, officers may search the person and the passenger compartment of the car. Professor Capra adds that the Supreme Court has also held that, where state law allows it, officers may take people into custody for minor offenses such as seatbelt violations or an illegal right turn on red, with fingerprinting and a thorough search to follow. All of this follows from the same principle: the officer's state of mind is not part of the test.
A Doctrine Unlikely to Change
Professor Capra calls the result a problem, and observes that the outcome turns on narrow details, such as whether state law authorizes an arrest, rather than on the broader question of whether the practice is right. But with a unanimous Supreme Court opinion anchoring the doctrine, he views it as unlikely to change.
What to Know Now
Professor Capra's assessment has held up. Whren remains the governing rule, and the Supreme Court continues to judge Fourth Amendment reasonableness in objective terms. Atwater v. City of Lago Vista upheld a custodial arrest for a seatbelt violation, and Virginia v. Moore later held that an arrest supported by probable cause satisfies the Fourth Amendment even when state law did not authorize it, so state limits on arrests are enforced through state law rather than the federal Constitution. The Whren Court itself pointed to the Equal Protection Clause as the constitutional basis for objecting to intentionally discriminatory enforcement, although such claims require proof of discriminatory purpose and effect and are difficult to win. Much of the change since then has come from legislatures and state courts. Virginia enacted a law in 2020 barring stops based solely on certain minor equipment violations, Philadelphia adopted a Driving Equality law in 2021 limiting stops for some low-level offenses, and Washington's highest court has long rejected purely pretextual stops under its state constitution. Supporters say these measures reduce racial disparities and needless confrontations, while critics argue they take away tools officers use to detect serious crime. For drivers, the practical point is that under federal law any traffic violation can justify a stop.
