Bluntly, Mr. Obama's partners are concluding that they cannot do business with him. They don't trust him. Whether it's the Saudis, the Syrian rebels, the French, the Iraqis, the unpivoted Asians or the congressional Republicans, they've all had their fill of coming up on the short end with so mercurial a U.S. president. And when that happens, the world's important business doesn't get done. It sits in a dangerous and volatile vacuum.