In a case called Mapp
vs. Ohio, 1961, the Supreme Court extended 4th Amendment
restrictions to all state governments. Before this time, the 4th
Amendment was only applied to the Federal Government.
Fourth
Amendment Court Cases - Katz
vs. United States
In Katz vs. United
States, 1967, a test was established that has been used
widely in judging 4th Amendment cases ever since. This is a two part
test that defines a search according to the 4th Amendment. 1) The
government's actions must infringe upon the person's subjective
expectation of privacy (meaning that it is the individual's opinion
that the place or thing to be searched is private), and 2) that the
expectation of privacy is reasonable, meaning that society in general
would agree that it is private.
Fourth
Amendment Court Cases - Dumbra
vs. United States
In Dumbra vs. United
States, 1925, the Court defined what is meant by probable
cause in the 4th Amendment. The Court ruled that probable cause was a
lesser standard than that used to convict a person of a crime. It also
said that if the circumstances would “warrant a man of reasonable
caution in the belief" that a crime had been committed, then probable
cause had been determined. The officer does not have to be correct in
his assumption that a crime had been committed, he just has to be
reasonably convinced by the facts.
Fourth
Amendment Court Cases - Terry
vs. Ohio
In Terry vs. Ohio,
1968, the Supreme Court allowed for a pat down search without a warrant
if the officer observed suspicious behavior and reasonably believed
that a crime was being committed. In this case, the Court said the
officer must be able to point to specific facts that led him to this
belief.