Case
Mapp v. Ohio
Answer: Mapp v. Ohio (1961). The Supreme Court held that the federal exclusionary rule applies to state criminal prosecutions via the Fourteenth Amendment, overruling Wolf v. Colorado. The decision grounded exclusion in deterrence and judicial integrity and set a federal constitutional floor for state courts. ([law.cornell.edu](https://www.law.cornell.edu/supremecourt/text/367/643))
Rule to remember
Mapp v. Ohio (1961) incorporated the Fourth Amendment exclusionary rule against the states, holding that unconstitutionally obtained evidence is inadmissible in state criminal prosecutions and overruling Wolf v. Colorado. ([law.cornell.edu](https://www.law.cornell.edu/supremecourt/text/367/643))
Key elements and checks
- Unconstitutional search or seizure (no warrant or outside a valid exception).
- Defendant’s own Fourth Amendment rights must be violated (no vicarious standing).
- Remedy: suppression in state prosecutions via the Fourteenth Amendment’s Due Process Clause.
- Overrules Wolf v. Colorado (1949), ending the federal–state “double standard.”
- Later cases limit exclusion (good-faith, attenuation, inevitable discovery), but these are federal minimums; states may provide greater protection.
In the source’s words
“We hold that all evidence obtained by searches and seizures in violation of the Constitution is, by that same authority, inadmissible in a state court.”
Dollree Mapp v. Ohio, 367 U.S. 643 (1961) — Opinion (LII)
“There is no war between the Constitution and common sense.”
Dollree Mapp v. Ohio, 367 U.S. 643 (1961) — Opinion (LII)
State constitutions may mandate broader suppression than the federal floor; prosecutors must check state-specific doctrines even when federal exceptions might apply.