Michigan Dept. of State Police v. Sitz, 496 U.S. 444 (1990), was a United States Supreme Court case involving the constitutionality of police sobriety checkpoints. By a vote of 6-3, the Court held that these checkpoints met the Fourth Amendment standard of "reasonable search and seizure."
[edit] Background
In the state of Michigan, the state police adopted the practice of using random sobriety checkpoints to catch drunk drivers. A group of Michigan residents sued on the grounds that their Fourth Amendment rights prohibiting unreasonable search and seizure were being violated.
As the dissenting opinion by Justice Stevens explains, "a sobriety checkpoint is usually operated at night at an unannounced location. Surprise is crucial to its method. The test operation conducted by the Michigan State Police and the Saginaw County Sheriff's Department began shortly after midnight and lasted until about 1 a.m. During that period, the 19 officers participating in the operation made two arrests and stopped and questioned 124 other unsuspecting and innocent drivers"
During the operation, drivers would be stopped and briefly questioned while in their vehicles. If an officer suspected the driver was intoxicated, the driver would be sent off for a field sobriety test.
Holding
The Supreme Court held that Michigan had a "substantial government interest" to advance in stopping drunk driving, and that this technique was rationally related to achieving that goal (though there was some evidence to the contrary). The Court also held that the impact on drivers, such as in delaying them from reaching their destination, was negligible, and that the brief questioning to gain "reasonable suspicion" similarly had a negligible impact on the drivers' Fourth Amendment right from unreasonable search (implying that any more detailed or invasive searches would be treated differently). Applying a balancing test, then, the Court found that the Constitutionality of the search tilted in favor of the government.
The conservative justices held that the limiting of 4th amendment rights had a negligible effect on the drivers and the common good outweighed the lessening of these rights.
What is interesting is that the liberal justices held for the 4th as written.
Much like your position on the TSA controversy.
