You don’t have to be a lawyer to work the street — but a handful of Supreme Court decisions shape almost every stop, search, and arrest you’ll make. Here are ten every officer should be able to recite in plain English, with the bottom line and the limit that costs cases. Each links to a full breakdown.
One rule before the list: these are the federal floor. Your state constitution, statutes, and department policy can be stricter — and often are. Know your state’s version of each.
1. Terry v. Ohio (1968)
An officer with reasonable, articulable suspicion may briefly stop and frisk for weapons — the foundation of the stop. Read the full breakdown →
2. Rodriguez v. United States (2015)
A traffic stop can’t be prolonged — even a few minutes — for a dog sniff without independent reasonable suspicion. Read the full breakdown →
3. Heien v. North Carolina (2014)
An objectively reasonable mistake of law can still support a stop — but not an unreasonable one. Read the full breakdown →
4. Whren v. United States (1996)
If a real traffic violation gives you probable cause, the stop is valid regardless of the officer’s true motive. Read the full breakdown →
5. Kansas v. Glover (2020)
A plate check showing the owner’s license is revoked supports reasonable suspicion to stop — unless you know the owner isn’t driving. Read the full breakdown →
6. Arizona v. Gant (2009)
Once the arrestee is secured, the automatic vehicle search is gone; only two narrow windows remain. Read the full breakdown →
7. Riley v. California (2014)
Seizing a phone incident to arrest is one thing; searching its data needs a warrant. Read the full breakdown →
8. Birchfield v. North Dakota (2016)
A warrantless breath test is allowed incident to a DUI arrest; a blood draw needs a warrant. Read the full breakdown →
9. Collins v. Virginia (2018)
The automobile exception doesn’t let you enter a home’s curtilage to search a vehicle without a warrant. Read the full breakdown →
10. Maryland v. King (2013)
A DNA cheek swab at booking for a serious arrest is a reasonable procedure, like fingerprinting. Read the full breakdown →
Why these matter on every shift
Together these cases cover the calls that go sideways: when you can stop, how long you can hold, when you can search the car, the phone, or the person, and what the reasonableness standard really asks. Learn the bottom line and the limit for each, and you’ll articulate better reports and lose fewer cases.
Frequently asked questions
What Supreme Court cases should every police officer know?
Start with Terry v. Ohio (stops and frisks), Rodriguez and Whren (traffic stops), Gant and Collins (vehicle searches), Riley (phones), Birchfield (DUI testing), and Maryland v. King (DNA) — the decisions that govern everyday patrol. Each is broken down in plain English above.
Do these cases apply in my state?
They set the federal minimum. Your state can require more — a stricter search rule, a narrower exception, a higher standard. Always check your state’s rule on top of the federal floor.
Carry the rule, not the guesswork. StreetSense puts plain-English statutes, source-verified case law, and step-by-step field guides in your pocket — all 50 states and DC, fully offline. Start the free trial.
StreetSense is an educational reference for law enforcement, not legal advice. Federal cases set the floor — your state constitution, statutes, and department policy can impose stricter limits. Always follow your state’s rule and your agency’s policy. App features and pricing change; verify current details on the App Store or Google Play.