Nearly two decades ago, U.S. neoconservatives put Syria on their “regime change” list and have maintained that goal to the present day, placing it ahead of even blocking the spread of Al-Qaeda-affiliated terrorism. That chaos has now drawn in Turkey as it advances its own geopolitical agenda, as ex-CIA analyst Paul R. Pillar explains.

By Paul R. Pillar

The conflict in Syria, complex even by the standard of civil wars, has not presented U.S. policymakers with anything close to a clear opportunity to weigh in on the side of good guys against bad ones. There have been too many bad guys on multiple sides of this war.

The understanding that the United States reached last month with Turkey, according to which the latter evidently agreed to focus more on countering the so-called Islamic State or ISIS as distinct from its other objectives in Syria, would appear to have simplified a bit the lines of contention in the war from the U.S. point of view. But only a bit, if that. Turkish military operations in the area since announcement of the agreement with the United States have focused at least as much on Kurdish militias as on ISIS.

A prominent feature of the U.S.-Turkish accord is the declared intention of both governments to exclude ISIS from a zone along the border area of northern Syria. Given continued uncertainties about Turkish priorities, major questions persist about just what this zone entails. The Al-Qaeda-affiliated Nusra Front has expressed its own uncertainties about this.

An even bigger question is: if this zone is not to be a depopulated no-man’s land, then who will control it and administer it? The ludicrously few vetted “moderates” trained with U.S. help are in no position to do so, and reportedly part of the understanding with the Turks was that Kurdish militias were not going to be allowed to move into any vacuum in the area in question.

A look at a map shows the prospective zone to be a useful plug of a gap in a cordon sanitaire along the northern border of Syria, useful from the U.S. point of view in reducing the ability of radicals from abroad, including from the West, to move into the “caliphate” and go to work for ISIS.

Turkey, which has been touched by ISIS violence on its own territory, ought to value such a barrier to inhibit ISIS infiltration in the other direction. But Kurdish forces already control most of the rest of the border region, making them the otherwise logical candidate for establishing a presence in the newly declared zone, and this means that the Turkish hang-up about Kurds comes into play.

The United States may have been more solicitous than it ought to be about such Turkish hang-ups, partly because of our own rigid reliance on lists and a “once a terrorist, always a terrorist” way of categorizing some groups and movements. The principal Syrian Kurdish armed organization, known as the YPG, is closely affiliated with the PKK, the Kurdish group that waged a long and bloody insurrection in Turkey, in addition to conducting terrorist operations in the West.

One need not excuse for a moment any of the PKK’s past political violence to realize that the PKK’s position on lists of terrorist groups ought not to be the deciding factor in what use should be made of the YPG in Syria today. An additional factor to consider is that the PKK had done much to move away from its violent path, and Turkish president Recep Tayyip Erdogan, to his credit, had done much to get a peace process with the Kurds underway. But more recently Erdogan, to his discredit, abandoned that process evidently for reasons related to his own domestic political and coalition-forming needs.

So the lines of conflict in the Syrian conflict are as complicated as ever. This does not mean that the United States cannot do some useful business there with other players whose goals and priorities are much different from our own. The United States and Britain did ally, after all, with Stalin’s USSR for the sake of defeating Nazi Germany. But we ought to recognize fully the differing goals and priorities. And unanswered questions about things such as the zone in the north need to be answered.

Paul R. Pillar, in his 28 years at the Central Intelligence Agency, rose to be one of the agency’s top analysts. He is now a visiting professor at Georgetown University for security studies. (This article first appeared as a blog post at The National Interest’s Web site. Reprinted with author’s permission.)