The news that the Obama administration supports Russian efforts to convene negotiations between Syrian President Bashar al-Assad’s government and opposition forces is a stunning reminder of where U.S. policy on Syria has devolved. As happened with the Russian chemical weapons proposal of 2012, Vladimir Putin is once again rescuing U.S. Syria policy from itself. The Moscow talks are not likely to succeed. But the announcement reflects a growing view in Washington that Mr. Assad, while a huge part of the problem, may also now be part of the solution. Washington will not abandon President Barack Obama’s “Assad must go”...