I tend to agree with James Kurth that Iran's sponsorship of terrorism actually provides us opportunities to deter the Islamist terrorist organizations they influence or control through deterring Tehran. (Ahmadinejad's nutty stemwinders notwithstanding, I think there are good reasons to believe the Iranian government seeks self-preservation.) Unfortunately, that requires a credible threat to hold Iran responsible for the actions of groups like Hezbollah while not replacing the Iranian government with a failed or failing state through some Iraq-like venture. That's a tough balance to reach when the next commander-in-chief will be someone either who sings "Kumbuya" or "Bomb Iran."