I've said this before. But perhaps it seems like hyperbole. So I'll say it again. The president's interests are now radically disjoined from the country's. We can handle a setback like Iraq. It really is a big disaster. But America will certainly surive it. President Bush -- in the sense of his legacy and historical record -- won't. It's all Iraq for him. And Iraq is all disaster. So, from his perspective (that is to say, through the prism of his interests rather than the country's -- which he probably can't separate) reckless gambits aimed at breaking out of this ever-tightening box make sense.
Of course attacking Iran will destroy the US as a world power. But at least George will have a real war and a real legacy. Right now, all he has to look forward to is creeping impeachment and a long slow withdrawal from Iraq, which is hardly the high-note ending he's hoping for.
Bush has no personal concept of failure. If something goes wrong, someone else is to blame. If a project looks like failing and he's obviously responsible, the project can't be allowed to fail.
Hence Iran, because Iraq is already over.
We're dealing with a teenager here. Attacking Iran makes no sense in the adult world. If you're a teenager and trying to make a point, it makes perfect sense as a grand gesture.