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Barack Obama sounds at his best when he channels George W. Bush. This week, at his nuclear summit, Obama has been tackling two issues deeply familiar to Bush: Iran's nuclear ambitions and nuclear terrorism. On Iran, Obama is making almost no progress. He comes out of meetings with Russia's Dmitry Medvedev or China's Hu Jintao and says he's got the Russians or the Chinese lined up to approve tough sanctions against Iran, but then Russian and Chinese officials tell the press that isn't so.

The purpose of sanctions on Iran is twofold: to put political pressure on Tehran to change course and to physically slow down its ability to import nuclear weapons ingredients. There used to be a third purpose: to show every option had been exhausted before military action was taken against...