Michigan v. Long

Supreme Court of the United States · 1983 · Criminal Procedure

463 U.S. 1032 (1983)

Updated July 27, 2026

Criminal ProcedureFourth AmendmentInvestigatory StopsProtective SearchesAdequate and Independent State GroundsTerry stopprotective searchvehicle search

Facts

Deputies observed Long driving erratically and at excessive speed shortly after midnight in a rural area, then saw his car swerve into a ditch. When questioned, Long was slow to respond, appeared to be under the influence, and turned back toward his open driver's door; the officers then saw a large hunting knife on the driver's floorboard. After a patdown of Long revealed no weapons, one deputy shined a flashlight into the car to search for other weapons, lifted the front armrest, and found an open pouch containing what appeared to be marihuana. Long was arrested, and a further search of the interior found no additional contraband; the officers later opened the trunk and found about 75 pounds of marihuana.

Issue

Whether, during a lawful investigatory stop, police may conduct a protective search of the passenger compartment of an automobile for weapons when they have a reasonable belief the suspect is dangerous and may gain immediate control of weapons. The Court also considered whether it had jurisdiction despite references by the Michigan Supreme Court to the Michigan Constitution.

Rule

Police may search the passenger compartment of an automobile, limited to areas in which a weapon may be placed or hidden, if the officer possesses a reasonable belief based on specific and articulable facts, taken together with rational inferences from those facts, that the suspect is dangerous and may gain immediate control of weapons. When a state court decision fairly appears to rest primarily on federal law, or to be interwoven with federal law, and the adequacy and independence of any possible state ground is not clear from the face of the opinion, the Supreme Court will assume no adequate and independent state ground exists unless the state court makes a plain statement that its decision rests on such grounds.

🔒

See the holding & full analysis

Create a free KwikCourt account to unlock the rest of this brief — and practice the case.

The court's holding and reasoning
Doctrine tests, pitfalls & exam hypotheticals
10 practice questions + 4 AI-graded essays on this case

Free sample · practice this case

Test yourself

One of 10 multiple-choice questions for this case. Pick an answer to see why.

At 1:30 a.m. in rural Montana, Deputy Elena Ruiz found Owen Mercer slumped over the wheel of a pickup stopped partly in a gravel lane. When Ruiz asked for his license, Owen stared blankly, then suddenly pivoted toward the open driver's door; Ruiz saw a metal hatchet on the front floorboard. After a patdown revealed no weapon, Ruiz looked under the driver's seat and inside the center console for other weapons.

If Owen moves to suppress a pistol found in the console, how should the court rule?

Explanation. The majority held that during a lawful investigative stop, officers may search the passenger compartment, limited to areas where a weapon may be placed or hidden, if specific and articulable facts reasonably warrant the belief that the suspect is dangerous and may gain immediate control of weapons. Owen's late-night condition, movement toward the open door, and visible hatchet support that belief. The fact that the patdown found no weapon does not eliminate the danger from weapons in the car.