Mr. Obama’s nuclear deal will fracture the Western alliance against Tehran. Most egregiously, we will lose the French, who have, despite their abysmal economy and the political chaos of the European Union, tried to hold a firm line against Iranian nuclear aspirations and Mr. Obama’s reflex for concessions. Faced with other countries rushing to the Iranian market and Americans who have given up the fight, the French will probably abandon us, as they did with Iraq 20 years ago. Without the French, economic sanctions on Iran would never have had much European bite.

Critics of Mr. Obama’s efforts are going to get lost in the technical details of this “framework” agreement. Yet behind all the one-year breakout calculations, the enormous question marks about verification and PMDs, and sustainable snap-back provisions, the ultimate issue remains: Are you willing to threaten war to get a better deal, and prepared to preventively strike if Tehran moves toward a bomb?

Whatever chance American negotiators had of stopping the Iranian nuclear advance depended on this threat, as Iranian President Hasan Rouhani revealed in his writings when he was in charge of nuclear negotiations with the Europeans after the U.S. invasion of Iraq in 2003.