[thoughtomator]

Warrantless electronic surveillance doesn't violate the 4th Amendment where there it is reasonable to do so. The 4th prohibits unreasonable searches. If someone's chatting it up with terrorists or supporters/financiers thereof, then listening in is a perfectly reasonable thing to do given the duty of the government to defend the nation against such threats.

[kesg]

Warrantless electronic surveillance doesn't violate the 4th Amendment where there it is reasonable to do so. The 4th prohibits unreasonable searches.

This is exactly right. Whether there was a warrant is merely one of several factors going into whether the search was reasonable. Until this case, courts never required the government to get a warrant when the purpose was solely to gather foreign intelligence (which, incidentally, is part of the President's inherent constitutional powers under Article II).