In his talk before the United Nations on Sept. 26, President Barack Obama had this to say about Iran: "America wants to resolve this (nuclear) issue through diplomacy, and we believe there is still time and space to do so. But time is not unlimited... a nuclear-armed Iran is not a challenge that can be contained... the U.S. will do what we must to prevent Iran from obtaining a nuclear weapon."
Earlier, on March 4, 2012, Mr. Obama put it more succinctly: "Iran's leaders should know that I do not have a policy of containment. I have a policy to prevent Iran from obtaining a nuclear weapon."
Behind this rhetoric is an implicit threat to use military force against Iran. Yet in the seven United Nations resolutions regarding Iran's nuclear program, there is nowhere a threat, whether contingent or not, of the use of military force. All but one of the resolutions invokes Chapter VII. What does Chapter VII say? It allows the Security Council to "determine the existence of any threat to the peace or act of aggression" and to take military and non-military action to "restore international peace and security."
Further, the UN Charter prohibits member states of the UN from attacking other UN member states. Thus if the U.S. does go ahead with a military attack on Iran, as things stand now it will be a violation of international law.
Assuming that things remain stable between now and the American presidential election (which is not certain, as there could be a wild-card action), and assuming Barack Obama is re-elected, which again is not certain, he will have to eat a certain amount of crow if he does not attack Iran. But this is not so grave: There are precedents for the U.S. backing off from commitments to stop nuclear weapons programs: Pakistan, North Korea.
So assuming that negotiations over the Iranian nuclear program will resume after the American presidential elections, as most observers think they will, we will have to see if the policy of stiffing the Iranians -- who abhor foreign pressure, in view of their both glorious and inglorious past -- will continue not to work; or whether U.S. concessions, which have not been forthcoming so far, will dent the ideological obduracy of he Iranian position.