India, Sept. 22 -- The six leaders of the Gulf Cooperation Council arrived in New York on Monday having calculated, with some care, exactly what they needed from the American president they were about to sit across from. The calculation was harder than it looked. The man they were asking for protection against the consequences of the Iran war was the same man whose decisions had shaped the war's current trajectory, and the man they needed to keep a robust military presence in the Gulf was the same one who had spent eighteen months signalling that American troops should come home.

Trump convened the leaders of Saudi Arabia, the United Arab Emirates, Qatar, Bahrain, Kuwait and Oman on the sidelines of the United Nations General Assembly t...