You’ve been pulled over for speeding. Or for making a right turn after missing that “No Right Turn On Red” sign. These are completely random examples and definitely not the two moving violations for which I’ve been pulled over.
Anyway, the police officer takes your license and registration. You’re just hoping they give you a warning and send you on your way. When the officer returns, they hand your license back. “Can you open the trunk for me, please?” Wait, don’t they need a warrant for that?
You’ve figured out by now that the answer to questions like this is “maybe” or “usually,” right?
The Constitution lays out all things search and seizure in the Fourth Amendment: “The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation.”
The Fourth Amendment always protects you inside your home, and, according to Katz v. United States (1967), even in public—at least wherever a “reasonable expectation of privacy” exists. Law enforcement must have probable cause (an adequate reason) to search you or your property.
The warrant, on the other hand, is how law enforcement generally proves they have probable cause. Although warrants are the rule, it sometimes seems like legal rules only exist for exceptions to be carved out of them.
There are a handful of situations where the police can conduct warrantless searches.
Most obviously, law enforcement does not need a search warrant if you give them permission, assuming you have legal access to what they want to search. Remember, you are allowed to give limited consent. You can give an officer permission to search, say, the glove compartment, but not the trunk. You can also revoke consent with a clear, unequivocal statement.
Law enforcement can also seize, without a warrant, evidence in “plain view.” If an officer is walking down the sidewalk, looks through your window, and sees a giant bag of hashish on your dresser, they do not need a warrant to search your home. If they took that peek from your lawn, climbed a ladder to get a better angle or used binoculars to see further than the naked eye, then any warrantless search would be illegal.
This concept likewise extends to “plain smell” and “plain feel.” If you get pulled over and your car reeks of marijuana, you’ve provided all the probable cause police need to search your entire vehicle.
Law enforcement can also carry out a “stop and frisk,” also known as a “Terry stop.” If an officer has reasonable suspicion that you’re engaged in criminal activity, they can temporarily detain and question you. If that reasonable suspicion doesn’t turn into probable cause in short order, they need to let you go. In the meanwhile, however, they can pat you down in the interest of the officer’s safety and seize anything they find without a warrant.
Police also don’t need a warrant if they are in “hot pursuit.” If you steal a purse in full view of law enforcement, and then outrace the pursuing officer to your house, they do not need a warrant to enter your home and search for the stolen item. They watched you steal it, which is more than enough for probable cause, and, if they don’t search your home immediately, you might destroy the evidence.
That leads perfectly into “exigent circumstances,” a fancy legal term for situations where, on the balance, your privacy rights are outweighed by other concerns. If law enforcement has probable cause that someone’s physical safety is in danger, evidence is in danger of being destroyed or a suspect might escape, they can enter your home without a warrant.
The exceptions above are not a complete list. In general, if law enforcement is asking your permission to search something, they probably don’t have legal permission yet. If they can legally search something, they more than likely won’t ask.
Unfortunately, many of these exceptions, although reasonable, are ripe for exploitation. “Sniff, sniff. Is that marijuana I smell? I guess I’ll have to search the trunk.” If something like that happens to you, remember that we have courts to deal with this sort of thing. Interfering with what you think is an illegal search could result in obstruction, or even resisting arrest or assaulting an officer if you make physical contact.
If you think your rights have been violated, contact an attorney or a civil liberties organization like the ACLU. They will know best whether there was a violation and what the best course of action will be.
Jacob Hillesheim is a Minnesota educator who has taught courses in American history, world history, military history, government and criminal justice and law. He holds master’s degrees in teaching and learning and in history. He has never—never—said “no” to ice cream.