Oh , baby.
Man, I hate posting links. And I despise random Bush administration ranting on blogs. But I'm posting this because it strikes me as one of the most ridiculous constitutional arguments I've ever had the misfortune to come across.
Reference: Fourth Amendment
When Abraham Lincoln suspended habeas corpus during the civil war, there were militias marching on Washington D.C. and rioting all along the war fronts (also: a civil war in progress). His action was overturned by the courts. The esteemed Mr. Lincoln went on to ignore the court order and set up military tribunals. Once war ended, the Supreme Court declared that so long as the civil courts are functioning (as they were during the war), it was unconstitutional to set up military tribunals.
Ignoring the fact that a government can apparently do what it likes until after the fact, it's likely that at some future date the Supreme Court might look at this current argument and strike it down. One would hope that it would be slightly more difficult to bypass the constitution than by simply declaring activities "a domestic military operation", a phrase chilling enough on its own without being used as a pretext for punching a government's defining document in the nuts.