AS the United States Congress debates intervention in Syria, the precedent of NATO’s 1999 bombing campaign in Kosovo is being cited to justify using military force against the government of Bashar al-Assad.

The United States should respond militarily to Mr. Assad’s use of chemical weapons to murder his own citizens. Yet as a matter of law and policy, the Kosovo war is no precedent for airstrikes against Syria.

It’s true that Russia and China were opposed to a United Nations Security Council resolution to authorize the use of force in Kosovo in 1999, and they are opposed to such a resolution on Syria today. But that is where the similarity ends....