Ever read the Fourth Amendment to the U.S. Constitution? Probably not, or you—like most Americans—would not be so accepting of its demise as a pillar of the freedoms guaranteed to us by the Bill of Rights. The Fourth is the one that guarantees “The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures. …”
As the wording of the amendment clearly states, it’s not just your home that is your castle. Dating back to the late 12th century, when English common law was first taking shape, this principle granted a person sovereignty over his space even if a tyrannical monarch was sitting on the throne. The Fourth Amendment goes further than that, extending your sovereignty over “houses, papers, and effects.” So even when you are traveling beyond the confines of your domicile, your fundamental right to a private space is protected.
That space can only be invaded by agents of the state under the Fourth Amendment’s narrowly prescribed parameters: “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.”