While Obama has yet to stake out a promising unequivocal position, if he does, the obstacles would remain formidable. The two biggest are the U.S. Congress and the Israeli government of Benjamin Netanyahu.

Even as positive signs emanated from Geneva, where talks took place last week, the war party in Congress was pushing new economic sanctions against the long-suffering Iranians, who have gone without needed consumer goods, including medicines, because the U.S. government has cut Iran off from the international trading system.