Read a summary or watch video of this energetic debate on how Washington should balance vitally important relationships with Turkey and the Syrian Kurds in the fight against the Islamic State.

On March 22, Andrew Tabler, Soner Cagaptay, David Pollock, and James Jeffrey addressed a Policy Forum at The Washington Institute. Tabler is the Martin J. Gross Fellow in the Institute's Program on Arab Politics. Cagaptay is the Beyer Family Fellow and director of the Turkish Research Program at the Institute. Pollock is the Institute's Kaufman Fellow and director of Fikra Forum. Jeffrey is the Institute's Philip Solondz Distinguished Fellow and former U.S. ambassador to Turkey. The following is a rapporteur's summary of their remarks.

ANDREW TABLER

With a string of terrorist attacks hitting Turkey recently and the Assad regime losing control over three-quarters of its territory next door, the Syrian Kurds have become a point of contention between Washington and Ankara. U.S. officials see the Syrian Kurdish Democratic Union Party (PYD) as a tactical ally with a seasoned ground force in the fight against the Islamic State (IS), while Turkey views it as a terrorist group closely linked to the Kurdistan Workers Party (PKK), which it is once again fighting at home.

In Washington policy circles, Turkey and the PYD are both seen as allies -- albeit very different ones -- against IS. Turkey shares a long border with Syria, ample military bases, and the second-largest armed forces in NATO, all critical assets in the campaign. At the same time, the PYD and its armed wing, the People's Defense Units (YPG), have been the most effective ground forces in taking Syrian territory from IS.

SONER CAGAPTAY

The Kurdish political landscape is divided across countries and political lines. On one hand, the PKK and PYD fall under the same Group of Communities in Kurdistan (KCK), an umbrella organization established by the PKK. On the other hand, things are looking good for Ankara in Iraq's Kurdistan Regional Government (KRG), where Turkey has built close ties through economic, military, and security cooperation. Even there, however, power is contested between the Kurdistan Democratic Party (KDP), which favors Turkey and stands against the PKK/PYD, and the Patriotic Union of Kurdistan (PUK), which favors Iran and shares its sympathies for the PKK/PYD.

Current U.S.-Turkish relations regarding the PYD can be defined as a working detente. Ankara is fine with Washington helping the group in operations east of the Euphrates River, but not west of it. And Washington is fine with Turkey hitting the PYD from areas near the border, even as the United States works with the group near Raqqa, deeper inside Syria. This compartmentalization has worked so far, but it could run into pitfalls if the weapons Washington is giving the PYD end up in the PKK's hands, or if Turkey accidentally hits embedded U.S. personnel while targeting PYD positions near the border.

The biggest threat to this working detente, though, is Russia's entry into the conflict. The PYD's self-declared autonomous region along portions of Syria's border with Turkey (called "Rojava") gives Moscow a permanent lever in Syrian domestic politics, another potential foothold in the Middle East, and a lever against Turkish president Recep Tayyip Erdogan. Russia's desire to undermine Erdogan after Turkey shot down a Russian military jet in November is well known, so the United States should work with Ankara to prevent Rojava from becoming the Kremlin's security client.

Moreover, the PYD has yet to show that it can coexist with Arabs, Turkmens, and other ethnic groups when it takes over territory. Until it passes this litmus test, its appeal will remain largely limited to Kurds, and its forces will risk being seen as occupiers in Arab lands when they score victories against IS.

For its part, the PKK has been unrealistic in its goals, attempting to take over cities in Turkey and declare autonomy as the PYD did in Kobane, Syria. Not only has this strategy failed, it has also decimated the Peoples' Democratic Party (HDP), a major pro-Kurdish political faction in Turkey. The party's popularity has imploded since the PKK resumed violent operations, diminishing hopes that Turks might soon embrace Kurdish demands for political and cultural rights. The PKK may also have inadvertently rewarded Erdogan -- the Turkish president is hoping to boost his image as a right-wing strongman, and renewed war with the PKK is helping him do exactly that. He might even be able to peel off enough votes from the right-wing Nationalist Action Party (MHP) to build a popular majority, which would allow him to amend the constitution via referendum and transform Turkey into an executive-style democracy with him at the top.

Accordingly, the United States should encourage rapprochement between Turkey and the PYD. This would give Ankara a cordon sanitaire against the Syria war, bolster the PYD as a U.S. ally against IS, and prevent Russia from establishing a deep security relationship with the Syrian Kurds. Such a goal would be more realistic if Turkey and the PKK reached a ceasefire. Washington could also use its leverage with the KDP to encourage the PYD to break off from the PKK, especially since the Iraqi Kurds control the only access route to Rojava other than Turkey.

In sum, there are two trajectories for the PYD going forward: establishing a contiguous Russian-backed Kurdish zone in northern Syria, or working with the United States while breaking away from the PKK. To facilitate the latter scenario, Washington should point out that if Ankara does not take the PYD's hand, the Syrian Kurds and even the PKK could become Moscow's security clients, with grave security ramifications for Turkey.

DAVID POLLOCK

Thus far, Washington has been remarkably quick and successful in improving its coordination with Syrian and Iraqi Kurds against IS. The long-term goal should be to nurture a relationship between Turkey and the PYD that resembles Ankara's relationship with the KRG. Turkey and the Iraqi Kurds used to be outright enemies and went through a historic transformation to get to where they are today -- the closest of friends in the region economically, militarily, and politically. That is an achievable goal for the Syrian Kurds as well.

The PYD and PKK might share regional aspirations, but they are actually after their own geographically defined self-interests. As the PYD achieved military success and de facto autonomy for Syrian Kurds -- its main constituency -- over the past five years, it became more and more separate from the PKK, forming its own interests and command structures. In 2012, the PYD decided that it would no longer fight Turkey directly or help the PKK do so, and it has kept that promise. Moreover, the PYD-controlled zone is the only portion of the Turkey-Syria border where guns, drugs, and money are not being smuggled, making the group the only partner that can help Turkey secure its frontier against the PKK, IS, and other threats.

Many people might disagree, but the PYD is not an enemy to Syrian Arabs. Members of the group have engaged in unfortunate episodes of ethnic cleansing in certain Arab areas such as Tal Abyad, but today the PYD has an allied militia consisting of at least 5,000 Arabs fighting IS and other enemies. The group could eventually be a key ally in liberating Raqqa and then leaving it to Arab militias to hold, just as the KRG's Peshmerga could be a key partner in retaking Mosul.

Yet the Syrian Arab opposition has had terrible relations with the PYD. If opposition elements had simply been friendly with the PYD, never mind united with it, they could have achieved a lot against the Assad regime. They remain unwilling to recognize any Kurdish ethnic rights, however. Their main argument is that the PYD is cooperating with the Assad regime, but there is little evidence of such support politically or militarily. To be sure, the PYD has avoided fighting regime forces, but that is a matter of looking out for its own interests, not a sign of cooperation with Damascus. Privately, Arab opposition members note that while they cannot formally recognize Kurdish autonomy, they realize the PYD will have to be included in post-Assad Syria.

As for Russia's role, although the PYD accepts weapons, intelligence, and significant diplomatic support from Moscow, this is eclipsed by the group's eagerness for additional American support. Currently, Russia is the only party calling for the PYD to be represented at the Geneva peace talks, so in that sense the group has become the Kremlin's partner by default. But that is not the PYD's first choice, and their partnership is certainly limited. Unfortunately, developments have pushed the PYD and Russia together, and in tandem they have become more of a threat to Turkey.

The PYD's relationship with Iraqi Kurdistan is extremely complicated, but the bottom line is that Kurdish political and military interests have diverged geographically over the past five years. Syrian and Iraqi Kurds are now distant, and for the most part they do not fight together or coordinate policies. More broadly, Kurds in Syria, Iraq, Turkey, and Iran have all chosen to abandon the pan-Kurdish political project in favor of separately securing their rights in their respective countries.

JAMES F. JEFFREY

President Obama decided to get more serious about IS after the San Bernardino and Paris attacks, yet he remains unwilling to deploy the forces needed to solve the problem. The Islamic State is a military problem that needs to be solved militarily, and finding effective ground forces is a necessary complement to airstrikes against the group. Both the Peshmerga in Iraq and the YPG in Syria have proven that they are the only ones Washington can rely on to retake territory from IS and hold it. Whether they can continue to do so in Arab-majority areas is uncertain, but it is possible under the right circumstances, and the U.S. government would most certainly welcome that outcome.

Washington also wants to prevent any parties from altering borders in the region. Such redrawing would be particularly worrisome because no one knows where it would end once it begins. The United States has a real interest in maintaining the borders of each country as they are.

Regarding the PYD, Turkey poses a real problem for any scenarios involving the group. President Erdogan has benefited politically from PKK violence, and he see the potential creation of a Kurdish state on his southern border as a serious threat. To be sure, he relented some toward the end of the Islamic State's 2014-1015 siege of Kobane, offering to assist the PYD, so he could conceivably do so again today. Therefore, pressing him to stop opposing the group is worth a try.

The PYD and PKK are closely linked, but that does not mean Washington should consider the former a terrorist organization. In U.S. law, having ties with a terrorist organization does not necessarily make one a terrorist, and U.S. officials should make that distinction clear in the PYD's case.

If Washington and the PYD are to work together more closely, however, the group has to find a political and military way to advance further into Syrian Arab territory. This means more than just working with the Democratic Forces of Syria, an umbrella group that includes Arab and Assyrian Christian fighters but is dominated by the PYD -- in addition, the Kurds must work with Syrian Arab tribes and communities on the way to Raqqa. The battle against the Assad regime is not a priority for the Obama administration, so the PYD will need to find a more effective way to fight the Islamic State if it wants to receive more U.S. support.

This summary was prepared by Cem Yolbulan.