Fourth Amendment:
“The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.”
Supreme Court (Katz v. U.S.):
“[S]earches conducted outside the judicial process, without prior approval by judge or magistrate, are per se unreasonable under the Fourth Amendment—subject only to a few specifically established and well delineated exceptions.”
“The Obama administration is seeking to make it easier for the FBI to compel companies to turn over records of an individual’s Internet activity without a court order if agents deem the information relevant to a terrorism or intelligence investigation.”