The SCOTUS created the Exclusionary Rule in Weeks v. United States, 232 U.S. 383 (1914) to prohibit the prosecution from using evidence against a defendant that federal law enforcement officials had seized from the defendant’s residence without a search warrant, a violation of the Fourth Amendment prohibition against residential searches without a search warrant issued by a neutral and detached magistrate upon a finding of probable cause to believe that the defendant’s residence contained evidence of a particular crime.
At first, the rule only applied to federal law enforcement officials, not to state law enforcement officials. The SCOTUS eventually extended the rule to cover unlawful searches by state law enforcement officials via the Due Process Clause of the Fourteenth Amendment in Mapp v. Ohio, 367 U.S. 643 (1961).
The rule is not absolute, however, because a person can consent to a search of their residence, so long as their consent is obtained freely and voluntarily, not as the result of an assault, a threat or a false pretense.
The consent exception has produced a number of sub-rules to deal with situations that come up frequently where one person (e.g., a girlfriend) voluntarily consents to a search of premises they share with another and the search turns up evidence that the prosecution seeks to use against the other person (e.g., a boyfriend).
Generally speaking, these sorts of cases are decided on the basis of whether the defendant had a reasonable expectation of privacy in the place where the evidence was discovered and seized. Consent to search a common area of a home is valid as to all occupants, whereas consent to search another person’s room is not valid. Similarly, consent obtained from a motel or hotel clerk to search a person’s room or from a landlord to search a tenant’s room or residence is invalid.
A closely related rule is the plain view doctrine. Pursuant to this rule, a law enforcement officer may seize evidence of a crime that he or she sees in plain view, if the officer has a right to be where they are when they see the item in plain view and the officer immediately recognizes the item as evidence of a crime. Therefore, if an officer knocks on the front door of an apartment in a building, someone opens the door and the officer looks over the person’s shoulder and sees drugs and paraphernalia on a coffee table in the living room, the officer may enter without obtaining a search warrant.
Exigent circumstances are another important exception to the search warrant requirement. For example, an officer may enter a residence without a search warrant if the officer is in hot pursuit of a fleeing suspect who enters into the residence to avoid arrest. Officers also may enter a residence without a warrant to prevent the destruction of evidence, such as an attempt to flush drugs down a toilet.
I have always taught my students, many of whom were police officers, to get a search warrant whenever possible to be on the safe side. Houses can be surrounded to prevent a suspect from escaping and search warrants can be obtained within minutes at any time of the day or night by telephone from the on-duty judge.
The Exclusionary Rule also applies to exclude involuntary statements (i.e., coerced confessions) obtained from suspects in violation of the Fifth Amendment and statements obtained from suspects in violation of their right counsel.
Mark O’Mara has not filed a motion to suppress evidence pursuant to the Exclusionary Rule and I do not expect he will because all of Zimmerman’s statements appear to have been voluntary and he waived his rights to remain silent and have counsel present.
You may want to make a note of this article for future reference in this and other cases that we may have reason to discuss.
EDIT: Since I mentioned the plain view rule, I also should have mentioned the plain feel rule, even though it has nothing to do with search warrants. The plain feel rule applies to Terry patdown searches for weapons. If the officer conducting the patdown search feels something that feels like a weapon, they can reach into the pocket and seize it. Same is true of something mushy or a prescription bottle that feels like drugs. As with plain view, the officer must have a lawful basis for conducting the patdown (i.e., officer safety after stopping someone to investigate a reasonable suspicion) or the item seized will be suppressed pursuant to the Exclusionary Rule.