The U.S. Constitution protects us from unreasonable government intrusion. Specifically, the Fourth Amendment limits law enforcement’s ability to search and to “seize.”
States also have their own constitutions and statutes, which often provide protections that are similar, if not nearly identical, to the Fourth Amendment’s. But sometimes those laws offer slightly more protection than the Fourth.
Whether state or federal, laws on search and seizure generally provide that officers can’t search you, your belongings, or your home, or seize anything from you—or even seize you—without reasonable justification. Usually, this justification is probable cause. And sometimes probable cause must be established through a warrant.
A search warrant is a document signed by a judicial officer or magistrate who is “neutral”—generally meaning not associated with law enforcement. The warrant must include a detailed description of the place or thing—or even person—to be searched and of whatever is to be seized. But the amount of detail a warrant really requires isn’t overwhelming.
For a search of a house, for example, it’s typically enough to identify the address. And even broad descriptions of the kinds of evidence officers can seize will often suffice. The U.S. Supreme Court once approved warrants that called for specified items “together with other fruits, instrumentalities and evidence of crime at this (time) unknown.” (Andresen v. Maryland, 427 U.S. 463 (1976).)
Warrants have to be somewhat specific, and at least moderately timely. The rule for federal court is a good illustration, generally requiring that warrants indicate that they are to be executed within 14 days and between 6:00 a.m. and 10:00 p.m. (Fed. R. Crim. P. 41(e).)
Officers often don’t need warrants in order to carry out lawful searches. In fact, courts have acknowledged such significant exemptions from the requirement that officers get warrants that some argue the exceptions have all but swallowed the rule. Here are a few of the scenarios that allow law enforcement to act without warrants:
Despite these exceptions, though, officers clearly need to get warrants in some circumstances, as when aiming to search a home. In a typical situation—where, for instance, there isn’t an emergency—the police need a warrant to enter your abode without your permission.
Officers occasionally need warrants in other situations, too, usually where the search is particularly invasive. For example, if a car is parked on private property and there’s no reason for urgency, they might have to get a warrant. They have to get warrants to search the cellphones of people they arrest. And, unless there’s some kind of emergency, they typically have to collect a warrant in order to intrude into someone’s body (for example, taking blood). (Riley v. California, 573 U.S. ___ (2014), Schmerber v. California, 384 U.S. 757 (1966))
To get a warrant, an officer must describe facts that establish probable cause to believe that whatever will be searched contains evidence of a crime. The typical warrant application involves a written affidavit, but sometimes officers can even apply by phone. The officer applying for the warrant must swear to the factual statement.
Suppose detectives suspect Jesse of selling methamphetamine out of his house. They’ve received tips from known, reliable informants to that effect. They’ve also surveilled his house, observing suspicious characters going into the home for only moments at a time and departing with conspicuous packages. In order to search his home, the officers would apply for a warrant and include a description of the above facts.
Once they have a warrant, officers obviously have to comply with it.
The police must limit any inspection pursuant to a warrant to the area the warrant describes. For instance, a warrant calling for search of a particular cellphone owned by a suspect won’t justify a search of all that suspect’s electronics. Plus, officers may look only where an object of their search might reasonably be. If they’re looking for a 55-gallon drum of methylamine, they can’t open a sock drawer.
On the other hand, if agents happen to notice obviously incriminating evidence that isn’t described in the warrant, they can usually grab it because of the plain view doctrine.
Before carrying out a search warrant for a home, officers must typically provide “knock notice”—that is, announce themselves and their reason for being there. Usually only after the occupant has denied them entry or no one has responded may they break through. (For more on knock notice and other issues around home searches, see When the Police Search Your Home.)
Neither suspects nor their lawyers have a chance to thwart a warrant before it’s been issued. That’s because the procedure to get a warrant is “ex parte” (“from one party”); it involves only law enforcement (and the judge or magistrate who rules on the warrant request).
Because defendants normally can’t contest searches before they happen, they’re left to challenge them after the fact.
If officers exceed the scope of a warrant—if they search beyond what the warrant allows—a judge will normally suppress the illegally obtained evidence. In one case, for example, officers had a warrant authorizing them to search the suspect’s “person.” The officers used the warrant as justification for an endoscopy procedure that turned up a packet of heroin from the suspect’s stomach. An appeals court found that the procedure exceeded the scope of what a reasonable officer would have believed the warrant allowed. The evidence was therefore inadmissible. (United States v. Nelson, 36 F.3d 758 (8th Cir. 1994).)
What if the warrant itself is invalid? Usually, a warrant being defective—for example, because an officer lied about there being probable cause—means the search is unconstitutional. Evidence the search uncovers will be excluded from trial.
But the U.S. Supreme Court has ruled that “the exclusionary rule” doesn’t apply if the police reasonably believe that a warrant is valid. In the relevant case, an officer applied for and obtained a warrant from a judge. After the fact, another judge determined that the officer’s affidavit didn’t establish probable cause for the search. But because the officer had acted in what the Court termed “good faith,” the Justices determined that the relevant evidence shouldn’t be excluded. (United States v. Leon, 468 U.S. 897 (1984).)
Updated November 12, 2015
