The Romney campaign had at time of writing on Friday sent out two separate e-mail press releases chiding the Obama administration for its "refusal to say whether Jerusalem is the capital of Israel."
Now it's worth noting this was long the easy rhetoric of some of the less serious contenders throughout the GOP primary. But coming from Romney, the party's nominee-to-be, it would signal something far more significant.
I suppose it's possible the Romney campaign is so unaware of the realities of the Middle East peace process, however moribund it may be, that they're unconcerned with just how inflammatory an American president's expression of support for an undivided Jerusalem as the capital of Israel would be to the Arab world. But even with the stumbles Mitt Romney has made this week on the international stage, that seems unlikely.
So, accepting that Romney is aware of the significance, it seems likely he's prepared to signal a very real, very controversial departure from decades of U.S. peacemaking policy, and put the weight of his potential presidency behind a declaration that he believes Jerusalem is Israel's capital. That would be a very big deal.
Update: July 28, 10:14 AM
Reader MR rightly points out that then-candidate Obama in a 2008 speech to AIPAC said that an undivided Jerusalem was and should remain the capital of Israel. That's true. But after Palestinian leaders reacted with dismay, his campaign quickly walked things back.