Obama simply will not risk a third war in the region. The Obama administration has accepted the reality of a nuclear armed Iran. It will do everything it can to restrain Israel and force the Israelis to live with the terrifying peace of mutually assured destruction. Just in case Netanyahu does not agree it might be a good idea to remove our big blue water ships from the confines of the Persian Gulf. China has armed Iran with the world’s most sophisticated shore to ship missiles.
Obama does not have the will to restrain Iran. War will happen no matter his (weak) efforts. And the scope of that war will shock even him.