Israel does not need the approval or cooperation of the United States if, and when, Israel decides to remove the threat of iranian nuclear weapons as they have already done with iraq. The presence of the Israeli Air Force's discarded fuel tanks in syria near the Turkish border demonstrates that Israel is already aware of this possibility of flying completely around American controlled Airspace in Iraq to strike at Iran. The fear that such action would provoke other muslim nations to go to war against Israel, doesn't take into account the level of animosity felt towards iran by it's arab neighbors to the south, the iranian backed regimes in syria and gaza have no strategic effect because they are too weak. iran's defiance of international nuclear-non-proliferation treaties is likely go unanswered by Israel, despite an obvious capability, while negotions with their arab neighbors continue.
Clashes between IDF and protesters in Bethlehem and East Jerusalem (Reuters)
from the article: Think tank: Israel could attack Iran's nuclear program alone