[…] one he exhibits in reaction to the first. Yet we are still left exactly where we have been, with the U.S. and anti-Assad rebels operating on non-converging parallel lines to incidentally contradict…, and no political and legal grounds for forcing the two lines together in the near term. Those […]

Thanks for the comment. I should have linked (and will add a link) to the post - "Collateral Casualty of the War against War" - in which I discussed the term, which is a common translation of the legal termĀ hostis humani generis, and which has been carried over, but possibly overextended, in the post-WWII international legal regime in the "crime against humanity." In applying the term to Assad, I am assuming the truth of the rebel case against him - that his depredations against his own people, typified by the mass atrocity at E Ghouta, including the systematic targeting of civilians and very widespread use of torture against prisoners, qualify him as a war criminal and disqualify him as an ally.

You point to a significant, easily forgotten premise: Under the Universal Declaration of Human Rights, the US (and the world or most of it) is explicitly committed to equating "humanity" with, effectively, a fundamentally liberalized polity. We claim to know what humanity is, and what constitutes a crime against it, in relation to universal "rights." The world is to be a liberal world in this sense. For us or all of us, "the liberal political order is synonymous with humanity itself." We are obligated, have agreed to and insist upon the obligation, to reject, defy, and indict violators of this finally liberal order. We are not, however, obligated to make war, or to engage in specific acts of war or specific "police actions," against them.

The result is a gray area or area of confusion and conflict in our interpretation of our responsibilities under the regime we claim to uphold, and from which we, the US, the West, and the UN system, derive our special prerogatives. We are left to seek legal justification for military action in the claims of sovereign states, including our own, while observers continually - understandably and often sympathetically, but not always reasonably - assess our conduct according to theoretical purely universal standards of justice, often to the exclusion of those same sovereign interests. So, for these observers, acting against IS because it has offended, injured, and threatened the United States is somehow unjust, or at best unimportant. For many, especially those in the region, Assad, who has committed far worse crimes by objective measures, just not against us directly, seems a far worthier enemy, but for us to embrace this judgment would be for us to adopt the interest of others, implicitly the whole of humankind, as our primary interest. We might like to think of ourselves this way, but action for the whole of humankind is "beyond" us. The world and probably the vast majority of those calling for US war on Assad do not really want the US simply to presume the right and responsibility to "destroy all monsters."

That the interests of the American politeia and those of the Syrian insurrectionists don't really coincide is a point well taken. It would of course be controversial to assert that issues like the civil war in Syria are best viewed through an illiberal or "realist" perspective, but even according to an assessment that stems from political liberalism and utilitarianism--which supposes that "good" or "bad" outcomes in the sociopolitical domain can largely be evaluated according to a calculus of the (mostly physical) pleasure or pain which they entail--the order that existed in Syria prior to the revolt was infinitely preferable to the current situation and so ought to have been sustained rather than destroyed.

The original post makes repeated use of a peculiar expression: the "enemy of humankind". To describe Bashar Assad--or even Islamic State--as the enemy of humankind would seem to be an exaggeration. Dismissing out of hand the notion that Assad is obliged to be a pacifist, it is imperative that he defend the politeia of which he is the representative head from those who would seek to destroy it. One might disapprove of that politeia without supposing Assad (or his regime-type) to be the metaphysical enemy of all humanity--assuming, that is, that one doesn't simply equate humanity with the liberal politeia.

The Islamic State is clearly the enemy of the liberal politeia. Unlike the liberal regime, which upholds itself as the only way of life whereby the humanity of men and women may be fully achieved and safeguarded, the Islamic State contends that Islam (or a "strict version" of Islam, as they say) is the only path whereon men and women attain to the complete and abiding realization of their humanity. It is certainly a different conception of human self-realization than the liberal one; but that just means that it is the enemy of the liberal political order, not the enemy of humanity as such--unless, of course, the liberal political order is synonymous with humanity itself.