William Kristol thinks Obama would be wise to take up the regime change mantle for Iran:
'Perhaps embracing the concept of "regime change" spooks the Obama administration. It's awfully reminiscent of George W. Bush. But one great failure of the Bush administration was its second-term fecklessness with respect to Iran. Bush kicked the Iran can down the road. Does Obama want an achievement that eluded Bush? Regime change in Iran -- that would be an Obama administration achievement that Joe Biden, and the rest of us, could really celebrate.
'
This is the last graf of Kristol's column, which is unfortunate because he doesn't really explore the question of why Bush was "feckless" with respect to Iran in his second term.
Maybe - just a guess - it had something to do with the previous regime change operation?