If the arguments being presented by President Obama and Secretary of State John Kerry for attacking Syria seem increasingly shrill and disjointed that might well be because a legitimate case cannot be made for going to war. The central argument—i.e., that punishing al-Assad will “change his calculus” and dissuade him from using chemical weapons against rebel forces embedded within the civilian population—relies on demonstrating that al-Assad has already done just that, a case that has not been...


