President Obama doesn't think so:
U.S. President Barack Obama told Channel 2 News on Wednesday that he believed Israel would not try to surprise the U.S. with a unilateral attack on Iran.
In an interview aired Thursday evening, Obama was asked whether he was concerned Prime Minister Benjamin Netanyahu would try to attack Iran without clearing the move with the U.S., to which the president replied "I think the relationship between Israel and the U.S. is sufficiently strong that neither of us try to surprise each other, but we try to coordinate on issues of mutual concern."
But Iran's nuclear program has thrown this commitment into sharper relief. What if Israel feels that its security needs can only be met by attacking Iran, whereas the U.S. believes that such an attack would put other American interests at intolerable risk? One party would be forced to live with greater insecurity as a result.