I think the WSJ is on to something.
In short the only claim that leftist moonbats have that the President violated the constitution would be based on the 4th amendments prohibition against warrantless searches and seizures. However this court revisited the issue and decided that the Thruong Case settled this question and that the President has "inherent power" to conduct these actions. (629 F.2d at 914)
I will also look up the Thruong case, but so far it looks pretty solid to me.
Here is a copy of the link tho the 2002 case. Its in adobe format. Its a long opinion,(56 pages) but the relevant quote is on page 48.
http://news.findlaw.com/hdocs/docs/terrorism/fisa111802opn.pdf#search='In%20Re%20Sealed%20Case%20FISA'
In case their is a problem with my link, here is some more info on the 2002 case.
United States Foreign Intelligence Surveillance Court of For Review
In re Sealed Case #02-001 (Consolidated with 02-002)
Argued on Sep 9, 2002
Decided on Nov 18, 2002
Opinion filed Per Curiam