Top 10 Cases for Police Series, Part 7

For more cases, see <a href=

Editor's Note: With so many cases affecting policing, the question often arises regarding which are the most important. If a law enforcement professional could choose only 10 cases to examine, which would those be? Included in this series is a list of what experts Rolando del Carmen and Jeffery Walker consider to be the top 10 cases most influencing day-to-day policing in the U.S. Continuing from our last installment, in reverse order, we give you number 4: Carroll v. United States, 267 U.S. 132 (1925).


The warrantless search of an automobile is valid if there exists probable cause to believe it contains contraband.


Officers observed the automobile of Carroll while on a regular patrol from Detroit to Grand Rapids. The same officers had been in contact with Carroll twice in the four months prior to this sighting. In September, the officers attempted to buy illegal liquor from Carroll, but he was alerted to their true identity and did not produce the contraband. In October, the officers recognized Carroll’s automobile returning to Grand Rapids from Detroit (a city possessing an international boundary and that was known as a city from which illegal liquor was regularly imported). The officers gave chase but failed to apprehend Carroll. Carroll was later apprehended. He and his companion were ordered out of the car. No liquor was visible in the front seat of the automobile. Officers then opened the rumble seat and looked under the cushions, again finding no liquor. One of the officers then struck the “lazyback” of the seat, tore open the seat cushion, and discovered 68 bottles of gin and whiskey. Carroll was arrested and convicted of transporting intoxicating liquor.


May officers search an automobile without a search warrant but with probable cause that it contains illegal contraband? YES.

Supreme Court Decision

The risk of the vehicle being moved from the jurisdiction, or the evidence being destroyed or carried off, justifies a warrantless search as long as such search is conducted with probable cause that the vehicle that is subject to seizure contains contraband.


“. . . [T]he guarantee of freedom from unreasonable searches and seizures by the Fourth Amendment has been construed, practically since the beginning of government, as recognizing a necessary difference between a search of a store, dwelling house, or other structure in respect of which a proper official warrant readily may be obtained and a search of a ship, motor boat, wagon, or automobile for contraband goods, where it is not practicable to secure a warrant, because the vehicle can be quickly moved out of the locality or jurisdiction in which the warrant must be sought.”

Case Significance

The general rule is that searches may be conducted only if a warrant has been issued. There are several exceptions to this rule, however, searches of automobiles being one of them. This case, decided in 1925, created the so-called “automobile exception” to the warrant requirement by ruling that warrantless searches of motor vehicles are valid as long as there is probable cause to believe that there are seizable items in the vehicle. The justification for this exception is the mobile nature of the automobile.

For many more cases, see Briefs of Leading Cases in Law Enforcement, 8th ed., which includes short, easy-to-understand briefs of 185 cases of primary importance to law enforcement


Vehicle Rampages

Developing a plan to stop a motor vehicle attack

Campus Policing: Changing the Perception

The ups & downs of becoming a campus cop

Dealing With Trust Issues

In a tight-knit unit, you can't abuse trusting relationships

Less Lethal Lessons

Alternative ways to stop a suspect

Predictive Policing Software

Helping agencies tackle crime trouble spots & trends

Police Divers & Underwater Investigations

In order to become a public safety or police diver, one must possess skills outside of those learned as a recreational SCUBA diver