David Ignatius makes the alarmist “credibility” argument to defend the mistake that Obama is about to make:

Using military power to maintain a nation’s credibility may sound like an antiquated idea, but it’s all too relevant in the real world we inhabit. It has become obvious in recent weeks that President Obama, whose restrained and realistic foreign policy I generally admire, needs to demonstrate there are consequences for crossing an American “red line.” Otherwise, the coherence of the global system begins to dissolve [bold mine-DL].

Ignatius makes the usual bad assumption that upholding Obama’s vague, ill-advised threat from last year is crucial to U.S. interests elsewhere, but his version of this argument is even worse. He takes for granted that “the coherence of the global system” depends primarily on whether or not other states take our threats of military action seriously. That’s not really true, but it also ignores the small problem that U.S. military action has often come at the expense of international law in the last twenty years, which does far more to undermine “the global system” than refraining from war in one instance.

The U.S. has taken some form of military action against another government at least once in almost every year for the last twenty-five years. No one could have any doubt that the U.S. is more than willing to use force to back up its threats. Nonetheless, the fear among “credibility”-obsessed Americans is that someone somewhere might actually think that the U.S. can avoid unnecessary conflicts for more than a year or two. This fear is evidently baseless. No matter how unwise or unnecessary our involvement is in most of these foreign conflicts, Washington will find a way to insert itself sooner or later.

Ignatius wrongly assumes that attacking Syria will discourage Iran from building nuclear weapons. He writes:

U.S. action against Assad may not deter the Iranians, but it will at least make them think twice about crossing Obama’s “red line” against their acquiring nuclear weapons.

At this point, it’s hard to imagine how other states would not take U.S. threats at face value. If anything, the U.S. suffers from the opposite problem, which is that its claims of being willing to negotiate and reach peaceful agreements are now very difficult for other states to trust. As pariah authoritarian states that the U.S. wants to intimidate see us, the danger is not that the U.S. won’t try to attack them or overthrow their leaders, but that there seems to be nothing short of acquiring nuclear weapons that will prevent that from happening. Iran’s government may learn lessons from the Libyan war and the impending strikes on Syria, but they are likely to be lessons about the desirability and “necessity” of nuclear weapons that Washington doesn’t want its leaders to learn.