William J. Brennan, Jr.

“ The Fourth Amendment, made applicable to the States by the Fourteenth Amendment, commands that 'no warrant shall issue, but upon probable cause, supported by oath or affirmation.' The question presented by this case is whether the Constitution requires that, at or before the time a warrant issues, the judicial officer make a permanent record of the evidentiary basis for its issuance. In this case the entire record of the proceeding on the application for the warrant consisted of the complaint for the warrant, a copy of the warrant and the return on the warrant. ”

“ The substantive right created by the requirement of probable cause is hardly accorded full sweep without an effective procedural means of assuring meaningful review of a determination by the issuing magistrate of the existence of probable cause. ”

“ Reliance on a record prepared after the fact involves a hazard of impairment of that right. It is for this reason that some States have imposed the requirement of a contemporaneous record. Thus, in Glodowski v. State, 196 Wis. 265, 271, 220 N.W. 227 (1928) , the Wisconsin Supreme Court stated that:
'It is an anomaly in judicial procedure to attempt to review the judicial act of a magistrate issuing a search warrant upon a record made up wholly or partially by oral testimony taken in the reviewing court long after the search warrant was issued. ”