It assumes it's own conclusion: there are basically two ways in which such a conflict can end: One side wins, completely, and totally; or a third party intervenes and restores order and civility between the factions.

That is an invention, unsupported babble, these things can and do end in many ways.

Which is not to say it's going to be pretty.

...it realistically identifies the nature of the conflict and the essential problem with ending such conflicts. It does not recommend intervention, it simply lays the alternatives on the line.

In fact, he clearly states the case against intervention" "Right now, there is absolutely no appetite in the United States for... intervention... the humanitarian disasters have not been enough to galvanize... action. There is nothing intrinsically important there for U.S. vital interests. Syria does not have significant oil reserves, nor is it a major trading partner. It is not an ally and was never a democracy. If Syria were merely to self-immolate, it would be tragedy for the Syrian people but extraneous to American interests."

He also state why (outside of humanitarian interests) we might consider intervention: "However if Syria's civil war spills over into the rest of the Middle East, U.S. interests would be threatened."

He also is very realistic about the long term costs of intervention.

The basic point is that Civil wars are much harder to end through negotiation and accommodation than are other conflicts because both parties are going to have to intimately live with each other after the conflict. There isn't a bright, clear line that separates the two and that can fence off and protect the antagonists from each other, as there is in conflicts between states.

This is a thoughtful and insightful article that will help us to understand the implications of whatever course we do decide to take and will help to get us past unrealistic wishful thinking.

Those are in fact the extreme outcomes, the undesirable outcomes, the outcomes that one ought to be working to avoid.

...the "premise" is not false. Though not inevitable, it is a reasonable expectation given the historical outcomes of past civil wars, especially those rooted in ethno-sectarian conflict.

South Africa could have gone down this road, but the leadership there, perhaps helped by the fact that the country was nominally a democracy, made the right decision. It is probably too late for the Syrian regime, however.

Sometimes the undesirable outcomes are the only ones that are within the range of realistic possibility. However, I'm open to your ideas on what alternatives might be available and how you think they might be achieved.