Iran is entitled to have nuclear weapons as much as the US, Israel, Pakistan, etc. The president is not entitled to threaten them. The US stood off the Soviet Union for 50 years without attacking them and their is no excuse for a change in policy. The rule on nuclear weapons is Mutually Assured Destruction and it is time for Israel to start playing the game by the rules before they drag us into WWIII.
U.S. to defend Syrian rebels with airpower, including from Assad (Reuters)
from the article: Obama: U.S. will do 'what we must' to prevent a nuclear-armed Iran