It is now become clear that neither diplomacy nor sanctions will halt the Iranian march toward nuclear weapons. Iran is today stronger diplomatically than it has been in years, as evidenced by the meaning of the nonaligned nations in Tehran. Iran is neither isolated nor alone in a world in which nonaligned nations form a majority at the United Nations. The sanctions, while hurting the Iranian economy and making life more difficult for the average Iranian, are having zero impact on the Iranian nuclear program, which according to objective intelligence reports, is gathering steam and moving even more quickly toward its ultimate goal of a nuclear weapon that will be a game changer. An Iranian nuclear weapon will end any dream of non proliferation. It will protect Iran’s surrogate terrorists, such as Hezbollah, under a formidable nuclear umbrella. And it will make an eventual nuclear war more likely. That is why US President Barack Obama rightfully took the containment option off the table and put the preventive military option squarely on it. Although I support President Obama’s policy with regard to the Iranian nuclear threat, I think he must take one further step if the combination of diplomacy and sanctions are ever to work. That step is to communicate to Iran—unequivocally and without any room for misunderstanding—that the Obama Administration will never allow Iran to develop nuclear weapons.President Obama has already made this point, but not in a way that the Iranians understand and believe. Language matters, and President Obama must now use language that commits him, in the eyes of the Iranians, to keep his promise that he will, if necessary, use military force to prevent Iran from developing nuclear weapons. Only if the Iranians truly believe that they will never be allowed to develop nuclear weapons will the combination of diplomacy and sanctions work. The message has to be this: Look, sanctions hurt. Diplomatic isolation from first world powers is costly. So why incur this pain and cost if you know you will never be able to achieve your goal? Not only must the Iranians believe that the United States will, as a last resort, use its overwhelming air power to destroy Iran’s nuclear weapons program, but the Israeli leadership must also believe that the Iranians believe it. Only then will Israel forbear from taking preventive self defense actions on its own.If the Iranians and the Israelis were to believe believe President Obama’s assurances that, as he put it, “I don’t bluff,” there would be a real possibility that Iran would abandon its nuclear weapons program. But even if the mullahs were foolishly to challenge the United States, and continue with the weapons program, the Israelis would have an enhanced degree of confidence that Obama would keep his word and stop Iran before it reached its deadly goal. Right now, despite President Obama’s best efforts, neither the Iranians nor the Israelis are sufficiently confident that he would carry out his threat. They know that there are those within the administration and among President Obama’s supporters who will discourage him from making an unequivocal statement or carrying out a threat, because they believe that sanctions and diplomacy alone will work, without the need for “saber rattling.” There are also those who prefer a policy of containment to the threat of military action. The Iranians are aware of this faction and are counting on them to prevail, if it comes down to a choice between allowing Iran to develop nuclear weapons and stopping them by military action. President Obama must make it clear that he has rejected this view and that he will employ military action if that is the only option other than a nuclear Iran.This is not a debate between peaceniks and warmongers. Every Israeli and American that I know wants peace. Everyone would love to see Iran stop developing nuclear weapons without a rocket being fired or a bomb being dropped. The dispute is about tactics and strategy. President Obama believes that the best way to avoid having to use the military option is to make Iran understand that he will in fact use it as a last alternative to Iran developing the bomb. Those on the other side of this debate believe that making such an unequivocal threat would constitute saber rattling, and that such rattling actually decreases the chance for a peaceful resolution of this difficult issues. President Obama is right and those who are opposed to his rattling some sabers are wrong. So let President Obama look the mullahs in the eye and persuade them that they simply do not have the option of developing nuclear weapons. The only two options they have are to stop or be stopped. Only if they believe this, is there any realistic likelihood that they will stop.