The fourth amendment is discussed with reference to whether a reasonableness standard (first clause) or a more strict standard (second clause) should be used to assess the validity of searches and seizures. The Warren court interpreted the second clause to require: (1) the police to obtain a particularized warrant from a neutral and detached judicial officer before they search and seize; (2) a probable cause requirement, that the police must have a fixed quantum of evidence or enough to establish probable cause to justify the intrusion; and (3) a definition of search and seizure that is broad enough to include non-trespassory invasions of privacy by wiretapping and electronic surveillance. The Warren court also interpreted the amendment to require the use of an exclusionary rule to enforce its commands. Examples are provided as to how the Supreme Court, since the Warren court, has narrowed the scope and effectiveness of the fourth amendment without explicitly overruling any Warren court decisions or the exclusionary rule itself. Cases are analyzed to illustrate how the Court has turned to a balancing test that measures the reasonableness of the search and seizure against the special needs of the government to enforce laws. The use of a reasonableness standard in conjunction with redefining probable cause allows more evidence to be admitted than under previous Warren court decisions. Three cases are discussed that found a search to be unreasonable even though there was probable cause. The author asserts that the use of a balancing approach gives the court the opportunity to further weaken the effect of the fourth amendment. 217 footnotes.