Last night Keith Olbermann had on his show a guy who is an expert in security, and if I remember it correctly, even worked in the Bush administration. He claimed that Bush could have put the warrentless wiretapping in the Patriot Act and that Congress would have gladly rolled over and given it to him. But certain lawyers kept it out of the act just so that they could maintain the principle that the President can do whatever he wants without the need for congressional OK.
In other words, the point of this whole exercise was not so much the spying, but laying the legal ground for a 'strongman' government. If he gets away with this, the whole Constitution could be seriously undermined. Which is, of course, exactly what Bushco wants.