Probable Cause Requirement
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.
The concept of “probable cause” is central to the meaning of the warrant clause. Neither the Fourth Amendment nor the federal statutory provisions relevant to the area define “probable cause” ; the definition is entirely a judicial construct. An applicant for a warrant must present to the magistrate facts sufficient to enable the officer himself to make a determination of probable cause. “In determining what is probable cause . . . [w]e are concerned only with the question whether the affiant had reasonable grounds at the time of his affidavit . . . for the belief that the law was being violated on the premises to be searched; and if the apparent facts set out in the affidavit are such that a reasonably discreet and prudent man would be led to believe that there was a commission of the offense charged, there is probable cause justifying the issuance of a warrant.” 1 Probable cause is to be determined according to “the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act.” 2 Warrants are favored in the law and their use will not be thwarted by a hypertechnical reading of the supporting affidavit and supporting testimony.3 For the same reason, reviewing courts will accept evidence of a less “judicially competent or persuasive character than would have justified an officer in acting on his own without a warrant.” 4 Courts will sustain the determination of probable cause so long as “there was substantial basis for [the magistrate] to conclude that” there was probable cause.5
- Dumbra v. United States, 268 U.S. 435, 439, 441 (1925). “[T]he term ‘probable cause’. . . means less than evidence which would justify condemnation.” Lock v. United States, 11 U.S. (7 Cr.) 339, 348 (1813). See Steele v. United States, 267 U.S. 498, 504–05 (1925). It may rest upon evidence that is not legally competent in a criminal trial, Draper v. United States, 358 U.S. 307, 311 (1959), and it need not be sufficient to prove guilt in a criminal trial. Brinegar v. United States, 338 U.S. 160, 173 (1949). See United States v. Ventresca, 380 U.S. 102, 107–08 (1965). An “anticipatory” warrant does not violate the Fourth Amendment as long as there is probable cause to believe that the condition precedent to execution of the search warrant will occur and that, once it has occurred, “there is a fair probability that contraband or evidence of a crime will be found in a specified place.” United States v. Grubbs, 547 U.S. 90, 95 (2006), quoting Illinois v. Gates, 462 U.S. 213, 238 (1983). “An anticipatory warrant is 'a warrant based upon an affidavit showing probable cause that at some future time (but not presently) certain evidence of a crime will be located at a specified place.'” 547 U.S. at 94.
- Brinegar v. United States, 338 U.S. 160, 175 (1949).
- United States v. Ventresca, 380 U.S. 102, 108–09 (1965).
- Jones v. United States, 362 U.S. 257, 270–71 (1960). Similarly, the preference for proceeding by warrant leads to a stricter rule for appellate review of trial court decisions on warrantless stops and searches than is employed to review probable cause to issue a warrant. Ornelas v. United States, 517 U.S. 690 (1996) (determinations of reasonable suspicion to stop and probable cause to search without a warrant should be subjected to de novo appellate review).
- Aguilar v. Texas, 378 U.S. 108, 111 (1964). It must be emphasized that the issuing party “must judge for himself the persuasiveness of the facts relied on by a [complainant] to show probable cause.” Giordenello v. United States, 357 U.S. 480, 486 (1958). An insufficient affidavit cannot be rehabilitated by testimony after issuance concerning information possessed by the affiant but not disclosed to the magistrate. Whiteley v. Warden, 401 U.S. 560 (1971).
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