After Iraq they will be more thorough in making a case for war.
I seriously doubt that. I think it would take another 9-11 to gain support for attacking Iran without major backlash in Congress and the populace. However, he's not going to have an easy time convincing people that Iran attacked us, because he lost trust when people began to realize that Iraq had nothing to do with 9-11. The Bush Administration would have to do a lot more to convince folks, but taking a look at all sides of an issue is not the President's strong suit.
Politically, I think he is spent. His own party has abandoned him, his neocon friends are mostly gone, and Democrats are itching to capitalize on the midterm elections. The only things he can do now in his lame duck 2 years left is hope the Green Zone is not bombarded and overrun with militias (or some other major setback befalls American troops), and hope he can avoid becoming impeached.