"It’s difficult virtually to the point of impossibility to have a grand strategy in a world that is so fluid"

But he said Obama faces something of “devil’s brew” as he deals with a world of proliferating aggressors and the palpable exhaustion of the American people for military engagement. “There’s an expectation especially since World War II that the United States and president in particular can command events,” he said. “That’s not true and less true today than ever.”

Presidential advisers argue that Obama’s foreign policy management has born fruit, from getting the Syrians to give up their chemical weapons to bringing Iran to the negotiating table over its nuclear program to engendering the trust and credibility with other leaders to get European nations to support sanctions against Russia and rebuild a global coalition to deal with the Islamic State threat…

But the official believes that this summer has been different. Obama’s taking the lead on sanctions against Russia — and pressing reluctant Europeans to join — and the airstrikes this month against Islamic State in Iraq have gone some distance in restoring allied confidence in the president.

“It’s not my job to defend the administration,” the official said. “But they have acted, more than I expected.”