Mike the Usurper wrote:
There are exceptions, but those have always been ruled by the courts under the "probable cause" clause of this. A major topic twenty years ago was a "good faith" exception. That was rejected. So what might constitute a "reasonable search" without a warrant?
If you can't get a warrant, it's an unreasonable search. Period.
In the time immediately preceding FISA, a number of courts squarely addressed the issue of "warrantless wiretaps". In both United States v. Brown, 484 F.2d 418 (5th Cir. 1973), and United States v. Butenko, 494 F.2d 593 (3rd Cir. 1974), the courts upheld warrantless wiretaps. In Brown, a US citizen's conversation was captured by a wiretap authorized by the Attorney General for foreign intelligence purposes. In Butenko, the court held a wiretap valid if the primary purpose was for gathering foreign intelligence information.
A plurality opinion in Zweibon v. Mitchell, 516 F.2d 594 (D.C. Cir. 1975), held that a warrant was required for the domestic surveillance of a domestic organization. In this case, the court found that the domestic organization was not a "foreign power or their agent", and "absent exigent circumstances, all warrantless electronic surveillance is unreasonable and therefore unconstitutional."
