If the west fails to take action and Israel does, it's going to set back the modernization of the Middle-East IMO. Arabs may agree to the U.S. stopping the likes of Hussein, but they are not going to buy off on Israel attacking a Moslem ruled nation like Iran.
Once Israel does this the hatred of the U.S. will grow ten-fold in the region.
What bothers me, is that the west might procrastinate on this issue until it's really screwed the whole thing up.
The case needs to be made, even if we need to bribe Russia into agreement, that Iran's leadership must change.
"hatred of the U.S. will grow ten-fold in the region"
Can't get any worst than it is right now.