As a result of the Kurds’ convincing victories over ISIS, the Kurdistan Workers' Party (PKK) took control of the significant part of Syria - northern and eastern regions. Most importantly they captured Raqqah – the capital city of ISIS and oil-rich region Deir ez-Zor.
Kurdish power in northern and northeastern Syria is divided into two branches: military and civil. First of all, there is a military coalition of Arabs and Kurds, SDF (Syrian Democratic Forces). It is led by Kurds coming from the PPU (People’s Protection Units, YPG) which is subordinated to the PKK. There is also a higher civil authority - the Democratic Syrian Council, led by Ilham Ahmed, a Kurdish woman, she is considered pro-American. There are some unions which are under control of two leaders: a man and a woman. The local Kurds of the PYD (Democratic Union Party) are subordinated to the central party leadership of the PKK in Kandil (Northern Iraq, where there are partisan bases and the zone controlled by them). Although disagreements exist between local Syrian Kurds and the leadership of the PKK, but the Syrian Kurds implement what the leadership orders.
At first glance it seems that the PKK, having taken control of a significant part of Syria, entrenched in the region. But this is not totally true. In reality, Kurdish authority faces many challenges.
First, there is a growing tension between the Kurds and the Arab majority in Raqqah and Deir ez-Zor. The discontent of the local Arabs is great and the Kurdish administration does not like many of them. The Arabs are dissatisfied with the Kurdish influence and power in areas where Kurds are relatively few. Kurds constitute the majority in some regions in the northern Syria, for example in Kobani. But in Raqqah and Deir ez-Zor there are very few Kurds, these are mainly Arab regions. In addition, the Arabs are annoyed that Kurdish women occupied command positions in local bodies of civil authority. Therefore, the Arab-Kurdish conflict in these areas is very likely. However, it is possible that the Americans, whose influence is very large here, will not allow it to flare up in a full-scale war.
Today, the Arab tribes in Deir ez-Zor depart from the ISIS and move to the side of the Kurds. The rapid onset of Kurds in this region, unlike Raqqah, is explained by this factor. The Kurds have almost no loss in Deir ez-Zor. This happens primarily because the Arabs realized the defeat of ISIS. But it does not mean that the Arabs love the PKK. Many local tribes or individuals have recently fought for ISIS.
In the future, the role of the leaders of the Arab insurrection against the Kurds can be assumed by some groups of SFA (the Syrian Free Army). But their struggle is not efficient.
The next most important problem of the PKK is the lack of local economy. The PKK took control of 20-25% of the territory of Syria and 80% of Syrian oil, but these areas are now extremely poor. The problem is that the Kurds themselves cannot sell oil. One of the main buyers of oil is Assad, in addition, Assad has specialists who could arrange the production of oil, but the Kurds do not have their own specialists. But in the case of cooperation with Assad, the PKK would have to share oil revenues with him. In addition, the Kurds would have more money, and they would become more independent from America. And US doesn’t want it. Therefore, the US tries to hinder the PKK to deal with Assad on oil.
Relations with the Americans, Turkey, Russia and Assad
In the summer of 2017, the USA completely curtailed the project of financing the Syrian Arab oppositionists against Assad. This project, which was lobbied by the CIA, was liquidated by Trump. But the Pentagon's project, aimed at supporting the PKK in Northern Syria, received great support from Trump. The Americans sharply increased the supply of weapons of the Kurds and supported their actions against ISIS by air strikes. For that reason, the Kurds were able to occupy Raqqah and a number of other districts. Simultaneously, the Americans deployed their troops on the borders of the Kurdish cantons of Kobani and Jazira, protecting them from attacks from Turkey. In other words, the PKK has the ability to transfer partisans from Syria to Turkey (where they are fighting with the Turkish army) and back, but Turkey is deprived from the opportunity to attack the Kurds in Syria.
However, the Americans severely restricted the supply of weapons to the Kurds of the PKK, they almost do not receive heavy weapons; do not receive tanks and artillery. All this is a concession to Turkey. Further, the Americans did not defend the third, the most western and isolated Kurdish region of Afrin. Therefore, this canton is currently most vulnerable to a possible attack by both Assad and Turkey. It is controlled by Russian troops, and they are demanding the transfer of Kurdish formations to the influence of Assad.
Can Assad and his allies - the Iranians and the pro-Iranian Shiite militias - attempt to clean up the PKK in Syria? This is a complicated question. The Americans warned that the Persians and their allies are Shiite militias, they will not be allowed into these regions. But there is no clarity about how the US will react to the invasion of these areas by Assad's forces. Without Iranian and pro-Iranian forces, Assad will be struggling with the Kurds. Nevertheless, limited conflicts and battles for certain areas cannot be ruled out.
PKK and Saudi Arabia
Some considers that the PKK gains possible support from Saudi Arabia (KSA). The Saudi representatives made several visits to northern Syria and negotiated with the PKK and the Americans. It was about possible investments and the participation of the Saudis in the extraction and processing of oil. This is due to the fact that KSA is opposed to Iranian influence in the region, while Assad is an ally of the Persians. However, due to the political changes in Saudi Arabia, today they are not dealing with it.