Warrentless Searches

This from John Hinderaker at Powerline:

I've been working on and off on the legal issues surrounding the NSA's interception of communications directed to al Qaeda members overseas, some of which originated in the United States. I haven't had time yet to write up a full analysis of the case law. For now, let me just say that the question does not appear to be close. Under all existing authorities, the NSA program, as we understand the facts, was legal.

For now, let me simply quote the November 2002 decision of the United States Foreign Intelligence Surveillance Court of Review, in Sealed Case No. 02-001:

The Truong court [United States v. Truong Dinh Hung, 4th Cir. 1980], as did all the other courts to have decided the issue, held that the President did have inherent authority to conduct warrantless searches to obtain foreign intelligence information. *** We take for granted that the President does have that authority and, assuming that is so, FISA could not encroach on the President's constitutional power.

And those are cases that deal with electronic intercepts inside the United States.  A fortiori, intercepts outside the United States that coincidentally sweep in messages sent from America would seem to be obviously within the President's inherent Article II powers. So far, I have found no authority to the contrary.