This is going to have to be brief, but there just isn’t. You can’t enforce an “international norm” on your own recognizances. There has to be some kind of internationally recognized process, and some kind of authorization. That is what puts the “collective” in collective security. Since the creation of the United Nations, the only legitimate justification for the unilateral use of force is self-defense. Nobody alleges that a strike against Syria is an act in self-defense.
Nobody is even seriously defending it under “responsibility-to-protect” which was the justification for the Libyan intervention (and the Kosovo war before that). RTP extends the concept of self-defense to the defense of others. It’s a highly suspect doctrine with obvious potential for abuse – potential that was very arguably realized in the Libyan case. But even this expansive mandate for intervention doesn’t apply to Syria, where we are not proposing to protect the rebels but to punish the Syrian government for its reported use of chemical weapons against civilians.
If we launch an attack on Syria, it will not be under any legal warrant whatsoever. But the entire public justification for an attack is the to punish Syria for a crime of war – that is to say, the justification is the need to uphold international law. In other words, an attack would be an open declaration that the United States arrogates to itself the right to determine what the law is, who has violated it, what punishment they deserve, and to take whatever action is necessary to see it carried out. If that’s liberal internationalism, then I’m a kumquat.
With each American intervention since the end of the Cold War, the fig leaf that America operates as the anchor state in some sort of collective-security architecture grows more and more tattered. After Syria, assuming the reports predicting an imminent American attack are correct, I’m afraid we will look like Tim Brooke-Taylor at the end of the famous “Cha Cha Cha” Monty Python sketch.
I cannot fathom why the President – and much of his party – want to make America look like that.