Jackson Diehl: During a tour of the Middle East in November, Secretary of State John F. Kerry portrayed the region as on its way to a stunning series of breakthroughs, thanks to U.S. diplomacy. In Egypt, he said, “the roadmap” to democracy “ is being carried out, to the best of our perception .” In Syria, a peace conference would soon replace the Assad regime with a transitional government, because “ the Russians and the Iranians . . . will make certain that the Syrian regime will live up to its obligation .” Last but hardly least, the Israeli-Palestinian conflict was on its way to a final settlement — by April. “This is not mission impossible,” insisted the secretary of state. “ This can happen .” Some people heaped praise on Kerry for his bold ambitions, saying he was injecting vision and energy into the Obama administration’s inert foreign policy. Others, including me, said he was delusional . Four months have passed, and, sadly for Kerry and U.S. interests, the verdict is in: del...