John Judis relies entirely on the awful “credibility” argument to call for military action against Syria:

Secondly, there is good reason for the United States, once it declares a “red line,” to observe it. Diplomacy is preferable to war, but where deep-seated conflicts loom, diplomacy rarely works unless backed up by the threat of force—and that means declaring “red lines.” NATO’s declaration of a “red line” in Europe helped prevent an armed conflict there with the Soviet Union. American promises to defend Taiwan or Japan may have prevented a conflict in Asia. Conversely, the failure to draw red lines in the Korean peninsula in 1950 or on the Iraqi border of Kuwait in July 1990 (“We have no opinion on your Arab-Arab conflicts,” the U.S. Ambassador famously told Saddam Hussein) helped lay the basis for war. If the Obama administration were to ignore its own “red line” in Syria, that would send a message not only to the Assad regime, but also to North Korea and Iran that it could ignore American threats.

NATO’s collective security guarantee was a pledge to defend one or more allies from an act of international aggression. The U.S. was and continues to treaty-bound to defend the other members of the alliance, just as it has been bound to defend South Korea and Japan for decades. Regardless of what the U.S. does or doesn’t do in Syria, no one thinks the U.S. is going to abandon its treaty commitments. Acheson’s omission of South Korea from the “defense perimeter” was a mistake, but that isn’t why North Korea invaded. It is silly to think that decades of standing American policy in Korea would lose credibility because the U.S. chooses not to attack Syria over what is at most small-scale use of sarin. Judis is engaged in fear-mongering here, and it’s not even very good fear-mongering at that.

Mixing up U.S. policy towards Iran with the response to Assad may be a product of muddling the differences between chemical and nuclear weapons under the WMD label. As critics of the WMD designation have correctly pointed out for a long time, these are two very different types of weapons that shouldn’t be lumped together under one name. The proliferation of the latter is properly considered a much graver development than the admittedly atrocious use of chemical weapons. Judis’ argument requires us to pretend that there is no difference in severity between nuclear proliferation and the uncertain reports of possible chemical weapons use. According to him, the U.S. must start a war in response to a small, possibly accidental use of sarin if its readiness to attack Iran can be believed. To state this argument plainly is to discredit it.