It can be argued that Obama’s decision to hold off on air strikes and negotiate with the Russians is better for the United States in the short run than the other two alternatives on offer — ineffective air strikes or a landslide repudiation of the commander-in-chief by Congress. But in the long run, it’s a terrible setback for America.

Richard Nixon and Henry Kissinger muscled the Soviet Union out of Middle East diplomacy back in 1973. In the 40 years since, American presidents have worked to keep the Russians out. Now they’re back in. A nation with a declining population, a weakened military, and an economy propped up only by oil and gas exports has suddenly made itself the key interlocutor in the region. Obama has allowed this even though it’s obvious that effective disarmament is impossible in a nation riven by civil war and ruled by a regime with every incentive and inclination to lie and conceal. The negotiations and any fig-leaf inspection process can be dragged out for weeks, months, and years, as Saddam Hussein demonstrated.

Obama said he hoped to degrade Syria’s chemical-weapons program. Instead he has degraded his own — and America’s — credibility.