Ezra Klein has a piece calling liberal hawks to task on their rhetoric on Iran. He argues that after getting burned by the obviously bad call to invade Iraq, they're trying to temper their rhetoric on Iran in order to cover their asses in case things go as bad as they did in Mesopotamia:
The new approach is not to refight the battle over the Iraq war, but to argue that those who got it right, or who got it wrong but eventually came to the right answer, are now in danger of overlearning the lessons of the war -- and missing the danger posed by Mahmoud Ahmadinejad. An elegant entry into this burgeoning genre comes from Ken Baer in the latest issue of Democracy. "[A] president's past mistakes," writes Baer, "can so preoccupy political leaders that they lose sight of the dangers ahead or the principles they hold dear." In the conclusion of his piece, he warns that progressives must "not use anger at one war as an excuse to blink when confronting a future threat head on."
...The remarkable thing about the growing liberal hawk literature on Iran is its evasiveness -- the unwillingness to speak in concrete terms of both the threat and proposed remedies. The liberal hawks realize they were too eager in counseling war last time, and their explicit statements in support of invasion have caused them no end of trouble since. This time, they will advocate no such thing. But nor will they eschew it. They will simply criticize those who do take a position.
Iran raises several complicated questions, but also a simple one: Do you think military force is called for in preventing Iran's pursuit of nuclear weapons?
I've also noticed this. There seems to be a lot of talk from liberal hawks for "getting serious about Iran," whatever that's supposed to mean. At least the right wing hawks explicitly call for bombing Iran, whereas the TNR crowd wants to have its cake and eat it too.