Does President Barack Obama want Syrian dictator Bashar al-Assad to fall? He's said he does, but fear of an interventionist slippery slope, re-election concerns, and anxiety about America's prominence in the Middle East have severely limited U.S. efforts to topple the Damascus regime. Shaming Russia into forsaking its Syrian ally appears to be the coup de grâce that Mr. Obama and his indignant secretary of state are still counting on.

This approach may not differ much from that of Mitt Romney, who has studiously avoided revealing...