Bret Stephens argues, rightly, that the failure to stop Iran's nuke dream will lead to either an Israeli strike or a nuke arms race in the Middle East.
Ronen Bergman has suggested, on multiple occasions, that Israel's historical precedent is one of preemptive action in the face of an existential threat. Barring some new twist and given that precedent and the pace of current events, my money is on an Israeli strike against Iranian nuke facilities before the end of 2010.
