The recent string of victories of the Syrian-Kurdish People's Protection Units (YPG) against the ISIL-held town of Tal Abyad, on the Syrian-Turkish border, and the seizure of an ISIL military base outside of the so-called Islamic State's declared capital of Raqqa, demonstrate how non-state militias have achieved greater success in this war against the Islamic State of Iraq and the Levant than the conventional militaries of Iraq and Syria.

Apparently the YPG's offensives were conducted in tandem with US air strikes, similar to the scenario in Tikrit, Iraq, where the US ultimately relented and launched air strikes along with an offensive led by the Iranian-allied Iraqi Shia militias.

In both Tikrit and Tal Abyad, it was the combination of US air power and an alliance with local militias that secured victory against well-entrenched ISIL fighters. In both cases, the US had allied with militias, not conventional militaries, that Washington had been wary of supporting.

The Syrian YPG is affiliated with the Kurdistan Workers Party (PKK), which is officially on the US state department's list of terrorist groups.

Kataib Hezbollah, an Iraqi Shia militia, is also on the list, yet it took part in the battle to expel ISIL from Tikrit, bringing the goals of the US and this Shia group together in the birthplace of Saddam Hussein.

Identity-based communities

The dynamics of these battles have forced Washington into an uneasy, de-facto alliance with militias like the YPG and Kataib Hezbollah. What these fighting forces have in common is that they view ISIL as an existential threat to their communities.

ISIL has proved determined to combat the Kurds of YPG, particularly in the past over the town of Kobane, not only for territory, but because the YPG's combination of secular, non-sectarian, ethno-nationalism is anathema to ISIL's transnational Islamist identity. ISIL has proven to target Shia Muslims for the simple reason that it has declared all members of the sect as non-believers.

ISIL represents a threat to both of these identity-based communities, and thus the militias of both groups have proven more motivated and tenacious in combating ISIL fighters, making them worthy partners with the US aim of countering ISIL.

The YPG victories have severed one of ISIL's primary arteries into Turkey itself, removing one of the links ISIL has utilised to sell black market oil and antiquities, in addition to serving as a conduit for its foreign fighters...

Granted, the YPG's fighting strength has been strengthened with Peshmerga fighters from the Iraqi Kurdistan Democratic Party (KDP), and the Shia militias include fighters from the Iraqi Dawa and Islamic Supreme Council of Iraq, all parties who began a working relationship with the US during their pre-2003 years as part of the Iraqi opposition.

However, the amorphous coalition against ISIL has allied the US with Iran as well, and Iranian-supported militias or PKK-affiliated groups, and the past precedents indicate that only when all of these elements cooperate can victories against ISIL result in depriving the group of territory on the ground.

Bizarre constellation of forces

Further victories may result from the deployment of more US Special Forces in the battle, or the much vaunted Iraqi forces retrained by the US at the moment, but as of yet, it is a bizarre constellation of forces that have achieved victory against ISIL, itself another bizarre constellation of purported former Baathists, local Iraqis and Syrian fighters, and foreign fighters, including a contingent of Western converts to Islam.

The YPG's success, however, will certainly alarm the Turkish state, concerned about the Kurdish resurgence on its border. The de-facto alliance between the US and YPG has alarmed Turkey and continues to fray US-Turkish relations. As the YPG is affiliated with the PKK, the Turkish security establishment no doubt worries about a resurgent Kurdish entity on its border.

Furthermore, a Turkish party, the HPD, which was given the blessing of jailed PKK leader Abdullah Ocalan to represent the aspirations of Turkey's Kurds, fared relatively well in the recent Turkish elections, entering the parliament and preventing the incumbent AK party from transforming Turkey into a presidential system under Recep Tayyip Erdogan. The combination of both recent events, signalling the empowerment of Turkish and Syrian Kurds, will certainly raise concerns among political elites in Turkey.

Furthermore, the YPG victories have severed one of ISIL's primary arteries into Turkey itself, removing one of the links ISIL has utilised to sell black market oil and antiquities, in addition to serving as a conduit for its foreign fighters who come to Raqqa via the area that surrounds Tal Abyad.

Too early to tell

While the Shia militias' victories in Tikrit in April were a blow to ISIL, the group counterattacked and seized the Iraqi city of Ramadi. While it is too early to tell what ISIL's response will be to YPG's victory, the YPG did not just deprive ISIL of territory, but severed a transportation route that sustained the group financially and in terms of recruits, in addition to delivering a symbolic blow against notions of ISIL's invincibility.

The YPG victories ultimately highlight the contest between two quasi-states, the so-called Islamic State and Rojava, the collective name of the de facto autonomous Kurdish regions that formed in north and northeast of Syria during its civil war. The two quasi-states are not only battling over the same territory in Syria, they reflect two competing models of governance in the area where the authority of the Syrian state has collapsed.

Each quasi-state is the antithesis of the other, yet both seek the trappings of statehood, ranging from national anthems to border guards and border crossings delineating the state itself.

Rojava highlights it multiethnic and multiconfessional diversity, housing Muslims, Christians, and Yazidis, while ISIL enforces religious homogeneity on the territory it conquers.

Rojava emerged from an ethno-nationalist Kurdish movement, creating a state for Syria's Kurds, whereas ISIL ostensibly repudiates nationalism, claiming it is a state of faith, albeit a state for Muslims as ISIL rigidly defines the faith.

New types of actors

Rojava highlights it multiethnic and multiconfessional diversity, housing Muslims, Christians, and Yazidis, while ISIL enforces religious homogeneity on the territory it conquers.

The recent YPG victories are significant in that they highlight a relatively new dynamic to conflicts in the Middle East. Instead of states with national armies fighting each other, which has primarily characterised conflict in the region since Israel was formed in 1948, what has emerged are new types of actors, quasi-states, with non-conventional militaries, combating each other.

Granted, Syria's civil war shares similarities to the civil war in Lebanon, where various warlords controlled their own fiefdoms through the mobilisation of confessional and ideological militias.

However none of the warlords in Lebanon had the potential of ISIL to destabilise large swaths of the Middle East and prove to be a security concern to both Washington and vast number of European states.

Rojava and the self-proclaimed Islamic State emerged within a civil war, but are embedded within a conflict with ramifications for the entire region. In a relatively small sliver of northeastern Syria beyond the Euphrates River, a battle is being fought to determine whether Rojava's secular, multiconfessional and multiethnic state can survive and in fact prevail against an Islamic state.

Ibrahim al-Marashi is an assistant professor at the Department of History, California State University, San Marcos. He is the co-author of "Iraq's Armed Forces: An Analytical History."

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.