No way in hell will the U.S. attack a country that actually has WMDs. That's what diplomacy is for.
Even if the US wanted to attack Iran, we simply don't have the resources and I seriously doubt we'll be able to pull troops out of Iraq in the next 4 years.
I hope you're right about the current President's interest in using diplomacy to avert war. Rememer, though, that we're not dealing with Ronald Reagan here; we're dealing with an administration which very suddenly and dramatically implemented a policy of preemtion in order to conquer a perceived "axis of evil" (which, in no uncertain terms, includes Iran). This "new way" is radical, even by ancient Roman standards, and we can't assume that the chess board looks like it did ten or 50 years ago.
I KNOW you're right about the lack of resources to launch another offensive in Iran. As some on this thread have suggested, the President and Congress may very soon be persuaded that the young civilian men (and perhaps women) of America can fill this void of resources, just as they have in past wars.
If history has taught us anything, it's that political momentum doesn't just fade away; it comes to a head. The President's current momentum, combined with our country's mass fear of radical Islamic terrorists, is an extraordinary force. It got a President reelected and it can conceivably get us into a much larger war in the Middle East. Logistics and practicality have taken a back seat to idealism and righteousness thus far for President Bush. Why assume that this will change now?