The Supreme Court has already rejected AG Gonzalez' legal defenses
Attorney General Gonzalez Assistant AG William Moschella has sent a letter to members of the House and Senate Select Committee on Intelligence. In the letter, Gonzalez Moschella re-states his belief that the President had the authority to engage in warrant-less snooping, in contradiction of the FISA statute.
However, the Supreme Court has already ruled against another President who tried a similar thing, saying this:
Of course, a state of war may in fact exist without a formal declaration. But no doctrine that the Court could promulgate would seem to me more sinister and alarming than that a President whose conduct of foreign affairs is so largely uncontrolled, and often even is unknown, can vastly enlarge his mastery over the internal affairs of the country by his own commitment of the Nation's armed forces to some foreign venture.
Gonzalez' Moschella's letter is a throat-clearing exercise in which Gonzalez the DOJ is stating most (if not all) of the arguments that will probably be stated in whichever court case hears both sides of the story. Legal minds greater than mine will address the various "precedents" that Gonzalez the DOJ uses to justify Bush's actions. I did notice that he quotes the Truong case as justification; others have already pointed out that this case does not say what Gonzalez the DOJ thinks it does. Whatever. That's why the case will go to court.
In doing some reading on this whole matter, I was impressed to discover that the Supreme Court has already had some relevant things to say about whether or not the President (under Section II of the Constitution) has the power Bush thinks he has.
In Youngstown Co. v. Sawyer, 343 U.S. 579 (1952) -- a case which expressly held that the President does not have the right to exercise his "inherent executive authority" in contravention of Congressional law:
"The doctrine of the separation of powers was adopted by the Convention of 1787, not to promote efficiency but to preclude the exercise of arbitrary power. The purpose was, not to avoid friction, but, [343 U.S. 579, 614] by means of the inevitable friction incident to the distribution of the governmental powers among three departments, to save the people from autocracy."Glenn Greenwald has the rest, including this tidbit from the majority opinion:
Of course, a state of war may in fact exist without a formal declaration. But no doctrine that the Court could promulgate would seem to me more sinister and alarming than that a President whose conduct of foreign affairs is so largely uncontrolled, and often even is unknown, can vastly enlarge his mastery over the internal affairs of the country by his own commitment of the Nation's armed forces to some foreign venture. 10 [343 U.S. 579, 643] . . . .You really have to read Greenwald article, if for nothing else that it is an excellent distillation of some of the arguments that will probably be brought to bear against Bush when this thing finally gets to court.
:: Update ::
Armando has more on the likely-relevant court cases that go against DOJ's arguments.