In a makeshift encampment at the Kurdistan Workers' Party (PKK) headquarters in the Qandil Mountains of Iraqi Kurdistan, a guerrilla commander is listening to a radio report about fighting in Syria between the Islamic State and Syrian Kurds affiliated with the PKK.

"The gun is the most powerful tool in the Middle East," the 27-year-old commander who goes by the nom de guerre Aziz and hails from Diyarbakir, the largest Kurdish city in Turkey, tells VICE News. "But the PKK needs the support of the people. It feeds off the people and has an obligation therefore to protect and get their support. We are ready to sacrifice ourselves for the people."

For more than 30 years, the PKK has been at the heart of the Kurdish nationalist movement in Turkey and the region at large. Seeking more rights and greater autonomy for Turkey's nearly 15 million Kurds, the PKK's battle-hardened guerrillas have fought the Turkish state to a draw. At least 40,000 people have been killed and hundreds of thousands displaced during the decades-long conflict, which has seen both sides commit abuses.

In late 2012, the Turkish state entered into direct negotiations with the PKK's imprisoned leader, Abdullah Ocalan, who holds godlike status for his role in what followers refer to as the "struggle." With a peace process and ceasefire in Turkey tentatively still holding, the PKK has turned its attention both to Syria and, due to the rise of the Islamic State in Iraq, Iraqi Kurdistan.

Since it's recognized by the US, Turkey, and European Union as a terrorist organization, the PKK's role in Syria, Iraq, and Turkey is a complicating factor as the United States and the international community develop a strategy to "degrade and destroy" the Islamic State.

Over the years, the PKK has developed into a transnational social and political movement with separate but affiliated parties in the four parts of Kurdistan — in Iran, Syria, Iraq, and Turkey — all of which fall under the umbrella of the Kurdistan Communities Union (KCK). Their message incorporates women's rights, human rights, environmentalism, communalism, and ''democratic autonomy,'' a grassroots form of democracy and governance viewed by Ocalan's followers as a model for governing in the Middle East and Kurdistan.

''The objective of the struggle," said PKK spokesman Zagros Hiwa, "isn't war."

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Numbering nearly 2 million, or 10 percent of Syria's population, the Syrian Kurds inhabit three noncontiguous areas in north and northeastern Syria, a region known to Kurds as Rojava. The PKK's Syrian affiliate, the Democratic Union Party (PYD), was established in Syria in 2003 from remnants of the PKK, which until 1998 received support from Syria. Since the rebellion against President Bashar al-Assad began in 2011, the PYD has followed a so-called ''third path'' of siding with neither the regime nor Arab opposition.

The PYD's armed wing claims to have at least 50,000 fighters — more than the CIA estimate of 20,000 to 31,500 fighters in the better-armed Islamic State. A cohesive and well-trained force, the PYD has proven to be the most effective fighters against the Islamic State, engaging in battles to protect territory and Kurds. The PYD's forces have been bolstered by PKK guerrillas, which have traditionally been composed of one-third Syrian Kurds.

The PYD has provided some semblance of governance, security, and inclusivity in the midst of an otherwise brutal civil war in Syria. In January, the PYD and more than 30 other parties, including minority Arab and Christian Assyrian groups, declared ''democratic autonomy'' in Rojava. But Salih Muslim, the head of the PYD, says they have no intention of breaking away from Syria and declaring independence.

Even US General Martin Dempsey, the Chairman of the Joint Chiefs of Staff, admitted the Syrian Kurds will be a necessary component of defeating the Islamic State.

Though hardly perfect, the interim administration includes councils, courts and police, and a progressive constitution that recognizes minority rights. Earlier this year, Human Rights Watch (HRW) released a report that found the PYD carried out arbitrary arrests against political opponents and failed to provide adequate due process in other cases. HRW also said "human rights abuses committed by the PYD and its security forces are far less egregious and widespread" than those committed by the Syrian government and other rebel forces. The PYD has since addressed some of HRW's concerns, which has included the demobilization of child soldiers.

The PYD's moves in Rojava have earned the ire of the Arab Syrian opposition, Turkey, the United States, and even the Kurdistan Regional Government (KRG) in Iraq. The PYD is accused of siding with the Syrian regime and monopolizing power, but the group denies the charges and explains it has no interest in joining an Arab opposition that doesn't recognize Kurdish rights. Nor does the PYD want to subject Kurdish areas to the destruction that has befallen the rest of Syria by fighting a regime that strategically withdrew from those areas in 2012.

Nevertheless, the PYD has both worked with and fought the regime and various facets of the rebel opposition whenever it has suited Kurdish interests.

Despite a variety of intra-Kurdish rivalries, the spread of the Islamic State and the inability of the Kurdish peshmerga in Iraq to handle the threat alone has opened up the possibility of greater cooperation between the PKK, PYD, and Iraqi Kurds. Fighting a common threat, a united front against the Islamic State is in the interests of the international community. Indeed, as the US supports the Iraqi Kurds in Iraq, a parallel Syria policy will have to involve the PYD.

In response to Islamic State advances, in June the KCK said its "guerrilla forces are ready to give any kind of support and fight actively, side by side with the [Iraqi Kurdish] peshmerga forces.'' The Iraqi Kurds and KCK have since called for greater cooperation and an end to political infighting between Kurds in order to face the common threat.

Since June, the PKK has moved to the front lines in Iraq, playing a key role in defending the country's Kurdistan region from the Islamic State. And it was the PYD that stepped in to fill the gap when peshmerga defenses collapsed in Sinjar, sending the Yezidi minority fleeing potential genocide at the hands of the Islamic State. The US bombing campaign that followed showed the potential for success of American and PYD cooperation.

Yet the Syrian Kurds, arguably the most moderate force on the ground, haven't received outside help. Instead, they have been isolated. Turkey, and until recently even the KRG, have often kept the border closed, going so far as to dig trenches and build walls. The US has so far refused to work with the PYD. This September the US again denied Salih Muslim a visa to the US for a conference on the Kurds held in Washington, DC.

Meanwhile, the Islamic State has moved heavy weapons captured in June from the Iraqi army in Mosul back to the Syria front. The weapons are being used against the outgunned Syrian Kurds, especially around Kobane, a key town on the Turkish border; more than 100,000 Kurdish refugees have flooded across the border to Turkey. In response to the unfolding attacks on Kobane, the PKK called for Kurds in Turkey to mobilize.

From his prison cell, Ocalan announced earlier this week that Kobane and the peace process in Turkey are inseparable. Allowing Kobane to fall, he said, would mean the end of the peace process.

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Some argue it's now time for the US to engage with the PYD.

"The US has sought to bypass or ignore PYD to please everyone else," said Aliza Marcus, a Kurdish affairs analyst and author of Blood and Belief: The PKK and the Kurdish Fight for Independence. "Free Syrian Army rebels, who don't want to give anything to the Kurds; Turkey, which opposes PYD because of its link to PKK; and the KRG. Washington's approach doesn't make sense, and at this point, it's counterproductive. It's time to include the PYD in any future discussions about the role Kurds can play in crushing ISIL in Syria and Iraq."

Even US General Martin Dempsey, the Chairman of the Joint Chiefs of Staff, admitted the Syrian Kurds will be a necessary component of defeating the Islamic State. "If you're asking me how does the opposition in Syria finally prevail against ISIL, I think it's going to require the assistance of in particular Jordanians and probably some of the Syrian Kurds and probably the Turks," Dempsey said at a mid-September hearing on Capitol Hill. Dempsey's statement implies that in order to effectively combat the Islamic State, Turkey and the PYD will have to cooperate.

Washington's Kurdish policy has effectively been determined by NATO ally Turkey and the PKK's status as a terrorist organization. Although the PYD is not recognized by the United States and EU as a terrorist organization, the US has generally followed Turkey's policy of ignoring or showing hostility toward the PYD and Syrian Kurds.

Rojava has become a major issue for Turkey's Kurds, who see it as a test for the PKK to rule and carve out a quasi-state.

"Rojava is an example for Turkey's Kurds," Riza Altun, a member of the KCK executive committee and one of five founding members of the PKK, told VICE News. Joking about how the US Treasury put a freeze on his ''nonexistent assets" for alleged drug trafficking, Altun said the US is continuing old policies regarding the Kurds and PKK despite changes in the region.

As the US and international community strike targets in Syria and Iraq from the air, the Syrian Kurds will stand to benefit. And with de facto control on the ground, the PYD is a necessary and willing partner. As Salih Muslim said following airstrikes in Syria, the PYD "would like to be a partner in this coalition against ISIL."

The Syrian Kurds don't pose a military threat to Turkey, nor have they ever threatened Turkey or the United States. Rather, the Syrian Kurds and the PYD pose an ideological and political threat to Turkey, and weaken the Turkish state's negotiating position in its ongoing peace process with the PKK. Turkey's Kurdish population sees no difference between Kurdish areas of Turkey and Rojava — they are the social, cultural, and geopolitical extension of each other.

Ultimately, to combat the Islamic State the US and international community will need not only Turkey and the Iraqi Kurds — the US can't continue to ignore the changing Kurdish dynamic of the region — but also the Syrian Kurds and their moderate fighting force with its popular support on the ground. To make this happen, a longterm solution lies in Turkey, and a resolution of its domestic Kurdish problem through the continuation of the peace process with the PKK.

How Turkey responds will determine the world's ability to fight the Islamic State.