Amendment 4
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.
Coverage of the Amendment
This amendment denounces only such searches and seizures as are "unreasonable," and is to be construed in the light of what was deemed an unreasonable search and seizure when it was adopted and in a manner to conserve public interests as well as the rights of individuals.[1] It applies only to governmental action, not to the unlawful acts of individuals in which the government has no part.[2] It has no reference to civil proceedings for the recovery of debts; consequently, a distress warrant issued by the Solicitor of the Treasury under an act of Congress is not forbidden, though issued without support of an oath or affirmation.[3] But the amendment is applicable to search warrants issued under any statute, including revenue and tariff laws.[4]
Security "in their persons, houses, papers and effects" is assured to the people by this article. Not only the search of a dwelling, but also of a place of business,[5] a garage,[6] or a vehicle,[7] is limited by its provisions. But open fields are not covered by the term "house"; they may be searched without a warrant.[8] A sealed letter deposited in the mails may not be opened by the postal authorities without the sanction of a magistrate.[9] The subpoena of private papers is subject to its test of reasonableness.[10] Retention for use as evidence of a letter voluntarily written by a prisoner, which, without threat or coercion, came into the possession of prison officials under the practice and discipline of the institution, is not prohibited.[11] Where officers demand admission to private premises in the name of the law, their subsequent explorations are searches within the meaning of the Constitution, even though the occupant opens the door to admit them.[12] A peremptory demand by federal officers that a person suspected of crime open a locked room and hand over ration coupons kept there was held not to amount to a seizure in view of the fact that the coupons were government property which the custodian was under a duty to surrender.[13] Neither wiretapping,[14] nor the use of a detectaphone to listen to a conversation in an adjoining room,[15] nor interrogation under oath by a government official of a person lawfully in confinement[16] is within the purview of this article. Nor does it apply to statements made by an accused on his own premises to an "undercover agent" whose identity was not suspected and who had on his person a radio transmitter which communicated the statements to another agent outside the building.[17] Said Justice Jackson for the Court: "Petitioner relies on cases relating to the more common and clearly distinguishable problems raised where tangible property is unlawfully seized. Such unlawful seizure may violate the Fourth Amendment, even though the entry itself was by subterfuge or fraud rather than force. But such decisions are inapposite in the field of mechanical or electronic devices designed to overhear or intercept conversation, at least where access to the listening post was not obtained by illegal methods."[18] But narcotics seized in a hotel room during absence of the owner, in the course of a search without warrant for either search or arrest, were not adducible as evidence against the owner, who, however, was not entitled to have them returned since they were legal contraband.[19]
Necessity, Sufficiency and Effect of Warrants
A warrant of commitment by a justice of the peace must state a good cause certain and be supported by oath.[20] A notary public is not authorized to administer oaths in federal criminal proceedings; hence a warrant based on affidavits verified before a notary is invalid.[21] A warrant of the Senate for attachment of a person who ignored a subpoena from a Senate committee is supported by oath within the requirement of this amendment when based upon the committee's report of the facts of the contumacy, made on the committee's own knowledge and having the sanction of the oath of office of its members.[22]
A belief, however well founded, that an article sought is concealed in a dwelling house furnishes no justification for a search without a warrant.[23] A warrant issued upon an information stating only that "affiant has good reason to believe and does believe" that defendant has contraband materials in his possession is clearly bad under the Fourth Amendment.[24] It is enough, however, if the apparent facts set out in the affidavit are such that a reasonably discreet and prudent man would be led to believe that the offense charged had been committed.[25]
The requirement of the Fourth Amendment that warrants shall particularly describe the things to be seized makes general searches under them impossible and prevents the seizure of one thing under a warrant describing another. As to what is to be taken nothing is left to the discretion of the officer executing the warrant.[26] Private papers of no pecuniary value, in which the sole interest of the Federal Government is their value as evidence against the owner in a contemplated criminal prosecution, may not be taken from the owner's house or office under a search warrant.[27]