Here's Krugman on Iran:
Why might Mr. Bush want another war? For one thing, Mr. Bush, whose presidency is increasingly defined by the quagmire in Iraq, may believe that he can redeem himself with a new Mission Accomplished moment.
And it's not just Mr. Bush's legacy that's at risk. Current polls suggest that the Democrats could take one or both houses of Congress this November, acquiring the ability to launch investigations backed by subpoena power. This could blow the lid off multiple Bush administration scandals. Political analysts openly suggest that an attack on Iran offers Mr. Bush a way to head off this danger, that an appropriately timed military strike could change the domestic political dynamics.
Bombing Iran would change the domestic political dynamics. The way things are headed, though, bombing Iran could be a major factor in Democratic victories in November.