Ask not what the Iranians can do...

I'm relatively pro-Israel -- relative to the people I know -- for now, because as I see it the Palestinian public is radicalized past all hope, and unlikely to accede to anything in the near future. (On the other hand, there is no doubt that the Israelis have been gratuitously brutal.) I'm also relatively pro-Iran, which has been ostracised for decades for no compelling reason. Therefore, I want to like this idea of R.W. Johnson's:

As it is the US has hugely strengthened Iran by handing Iraq over to Shi’ites and an Obama administration might try to capitalise on that by making a US-Iranian deal the cornerstone of Middle East politics, thus reducing Syrian, Saudi and Egyptian leverage. Iran would obviously be greatly tempted by such a deal. But if Obama and Ahmadinejad really could reach a deal it would probably be very bad news for both Hizbullah and Hamas, who might get cut off from Iranian aid. If that happens, I can’t see much joy for Palestinian militancy.

Unfortunately, I don't think it makes sense. Iran wants to be the dominant player in the Middle East; it has essentially succeeded at this, through its support of Hamas and Hezbollah, and the American fiasco in Iraq. This being so, I don't see what the Americans have to offer Iran, politically, to make them give up the regional prestige that comes from backing anti-Israeli militias.