In February, indications of an incoming Turkish military operation targeting the Kurdistan Workers Party (PKK) in Sinjar, northern Iraq led to a flurry of Iranian-backed militia activity targeting Turkey. Qais al-Khazali, leader of Asaib Ahl al-Haq (AAH), one of the most prominent Iranian-aligned militias in Iraq, hinted that the focus of his group’s activities could switch to Turkey instead of the United States (Rudaw, March 4). Al-Khazali even urged the Iraqi government to consider cooperating with the United States militarily to counter Turkey (al-Etejah, March 30).
Despite the Iranian-backed militia threats toward Turkey, Turkish military operations in northern Iraq expanded in June to include Makhmour, a refugee camp that Turkey claims is an incubator for PKK militancy, and is roughly 180 kilometers south of the Turkish border (Rudaw, June 7). Now that Turkey is once again striking deeper into Iraqi territory, the question remains—how will Iranian-backed militias respond? 
Turkish Military Expansion into Iraqi Kurdistan
Turkish military activity targeting the PKK in Iraqi Kurdistan is nothing new. Turkey has launched multiple military incursions in the territory since the 1990s aimed at reducing PKK cross-border capabilities (Terrorism Monitor, May 7). In recent years, Turkey has intensified its military operations and increased the number of military checkpoints and bases in the country (Rudaw, June 7, 2020). Such activities have largely been focused on the mountainous border region and around the Qandil Mountains near the Iraqi-Iranian border, where the PKK has based its headquarters since 1998.
The PKK and PKK-affiliated militants also maintain a presence further south in Iraqi territory, including in the aforementioned Sinjar (Nineveh Governorate) and Makhmour (Erbil governorate) areas. Both of these territories are the subject of disputes between the Kurdistan Regional Government (KRG) and the Iraqi federal government.  Sinjar, in particular, is of strategic importance to the PKK due to its proximity to Syria, which allows the PKK to link with the affiliated People’s Protection Units (YPG) Kurdish militant group in Syria. 
Sinjar’s PKK and PMU Alliance
Sinjar, a historically Yazidi region, came under the control of the Islamic State (IS) in 2014. A coalition of Kurdish forces, including the PKK, liberated the territory from IS in 2015, with assistance from Iranian-backed militias embedded within the state-sponsored security organization known as the Popular Mobilization Units (PMU) (Terrorism Monitor, December 17, 2020). The 2017 expulsion of KRG forces from Sinjar, ordered by pro-Iranian former Iraqi Prime Minister Haider al-Abadi, left the PKK and PMU in control of the territory. This brought the PKK into an alliance with the PMU, with several PKK-affiliated groups such as the Sinjar Resistance Units (YPS) officially joining the PMU by 2019.
Current Iraqi Prime Minister Mustafa al-Kadhimi, who has been keen to diminish the influence of the Iranian-aligned PMU militias, entered into the “Sinjar Agreement” with the KRG to reestablish formal Iraqi government control in Sinjar in October 2020 (al-Hurra, October 9, 2020; Terrorism Monitor, December 17, 2020). The goal is to regain control over the territory by removing the PKK, while simultaneously preventing Turkey from using Sinjar as a reason to expand its military presence deeper into Iraq.
Iranian-Backed Militias’ Reaction to Turkey’s Sinjar Threats
The Sinjar Agreement initially had Turkish backing. However, Turkish President Recep Tayyip Erdoğan reportedly became frustrated by the agreement’s perceived lack of progress, and threatened to launch a joint Turkish-Iraqi military operation in Sinjar in January (Middle East Monitor, January 23). The subsequent killing of 13 Turkish citizens who were kidnapped by the PKK in the Gare region of Iraqi Kurdistan led Erdoğan to renew threats against the PKK in Sinjar in February (al-Monitor, February 17).
Following increased Turkish threats of escalation in Sinjar, the Iranian-backed militias of the PMU responded uniformly to deter Turkey. Three PMU brigades were sent to Sinjar to bolster the already sizeable PMU presence in the area (Shafaq, February 14). Prominent militias, including AAH, Harakat Hezbollah al-Nujaba, and the Badr Organization, all threatened Turkey with military action if Turkey launched any major operation in Sinjar (Al-Nahar, February 14). AAH’s al-Khazali, in an attempt to turn public opinion against Turkey, went on Iraqi television claiming that Turkey represented more of a threat to Iraq than the United States (al-Etejah, March 30). Al-Khazali further stated that he would personally take up arms if Turkey were to follow through with what he described as “neo-Ottoman desires” to occupy and annex parts of Iraq. Most notable of all, a PMU militia is highly likely to have been behind the April 14 rocket attack on the Bashiqa Turkish military base in northern Iraq that killed one Turkish soldier (Rudaw, April 15; Militant Leadership Monitor, June 4). 
The Iranian-backed PMU militia’s show of force appears to have at least temporarily deterred a major Turkish military operation in Sinjar. Since Erdoğan’s Sinjar threats, the Turkish military launched Operation Claw-Lightning, which focused on the usual PKK targets in the Metina, Avashin, and Basyan areas near the Turkish border (Middle East Eye, April 24). While the Turkish military also launched an airstrike on a refugee camp in Makhmour on June 5, no significant Turkish military action occurred in Sinjar.
With the PMU highlighting its readiness to attack Turkish forces, Turkish reluctance to internationalize its conflict with the PKK was made apparent. Ankara argues that the PKK should continue to be seen as a domestic issue only, despite its presence outside of Turkey and its links to the PMU. This was particularly clear after the Bashiqa attack. Despite the loss of Turkish lives, Turkish Foreign Minister Mevlüt Çavuşoğlu refused to directly blame the PMU despite their obvious links to the attack. Instead, Çavuşoğlu preferred to refer to the perpetrators as militias that support the PKK (Anadolu Agency, April 20).
Risks for Erdoğan
While Erdoğan’s Justice and Development Party’s (AKP) strong rhetoric and action against the PKK may resonate with a domestic audience, risking Turkish lives fighting Iraqi militias could quickly become quite unpopular. This would particularly be the case given the considerable international backlash that would likely follow any attack on Sinjar, since it would threaten to reignite conflict in a region that had only recently suffered genocide and brutal conflict with IS.
While Turkish military superiority could overwhelm the PKK-affiliated militias, even with the support of the PMU, the conflict would also risk jeopardizing Turkey’s important economic relations with Iraq and Iran. Iraq is highly likely to condemn Turkish unilateral military operations in Sinjar and is equally too constrained by domestic politics to participate in a joint Turkish military operation. Turkish action in Sinjar would then risk its important economic relations with Iraq and the KRG, which include a set target of $20 billion in bilateral trade (Anadolu Agency, December 17, 2020). Likewise, Turkey is reluctant to risk its economic links to Iran by attacking Iranian-backed militias, which play a key role in Iran’s Iraq foreign policy, although due to U.S. sanctions bilateral trade with Iran has decreased.
Turkey’s Inadvertent Justification for Iran’s Militias in Iraq
Sinjar is important for the Iranian-backed militias for two reasons. The first is to maintain PMU influence over Sinjar, which provides a crossing point into Syria. While the PMU already controls border crossings in al-Qaim and al-Anbar, the diversification of routes into Syria further minimizes the risk posed to militia access to the country. Access to the Sinjar Mountains is also significant because it provides militia groups scope to attack Israel, with Iraq previously firing Scud missiles toward Israel from the Sinjar Mountains in 1991 (al-Monitor, November 13, 2017).
Secondly, initiating hostilities with Turkey provides renewed justification for the continued existence of pro-Iranian militias in Iraq. These militias have defended their privileged position in Iraq, where they are embedded within the state but operate independently, by claiming that their presence is necessitated by the alleged U.S. military occupation of Iraq. The continued U.S. withdrawal from the region has meant that these groups will eventually no longer be able to resort to the U.S. military presence as justification for their continued use of arms unsanctioned by the state. By inflaming the crisis with Turkey, these groups hope to find the same domestic credibility that they had when they were fighting to push U.S. forces out of Iraq. With the Iraqi general elections planned for October, in which many of the political wings of these militias will compete, switching the focus of the militia narrative to fighting to defend Iraqi sovereignty against Turkish encroachment could be a clever move.
Such a strategic and rhetorical shift of the Iranian-backed militia narrative from the U.S. to the Turkish military presence in Iraq would not be straightforward. The pro-Iranian militia support base is largely limited to the Shia-majority central and southern regions of Iraq, which lack significant cultural links to the ethnically and religiously diverse disputed northern Iraqi territories and the Sunni Iraqi Kurdistan autonomous region. Without Turkey directly attacking Shia militia interests, its largely Shia support base is unlikely to consider Turkish military activity as relevant. This would especially be the case if Turkey limits its military activity to the mountainous border regions in Iraqi Kurdistan with only the occasional airstrike or drone attack on Sinjar or Makhmour.
The pro-Iranian militia support base, therefore, requires a more dramatic confrontation between the Iranian-backed militias and the Turkish military for the Turkish occupation of northern Iraq and Iraqi Kurdistan to appear relevant. However, Iran’s own strategic interests with Kurdish militant groups mitigates the possibility of significant military conflict with Turkey. Iran has no real ideological alignment with the PKK or other Kurdish militant groups. In fact, Iran suppresses Kurdish autonomy movements in northwestern Iran. If pro-Iranian militias were to force a withdrawal of the Turkish military from northern Iraq and Iraqi Kurdistan, then it would free up PKK capability in the country to focus on other targets. This is a prospect that Iran would be keen to avoid. In particular, it could lead to the formation of a Kurdish crescent linking Kurdish militants in Syria to Iraq and through to Iran’s own domestic Kurdish militant group—the Kurdistan Free Life Party (Partiya Jiyana Azad a Kurdistanê—PJAK).
This has meant that while pro-Iranian militias may seek to increase anti-Turkish rhetoric, Iran is likely to give the green light to the militias to launch significant military activity against Turkey only in areas where Iran’s interests are directly affected, such as Sinjar. Likewise, Turkey, despite its bellicose rhetoric, is equally reluctant to intensify military operations outside of its usual Iraqi Kurdistan targets. This limits the capability of the pro-Iranian militias to act on their anti-Turkish rhetoric with the result that its anti-Turkish narrative risks being exposed as lacking relevance to its own support base.
 Turkey previously bombed Makhmour in 2017 and 2020 (Rudaw, April 15, 2020).
 In Sinjar and Makhmour, local militant groups, such as the Sinjar Resistance Units and the Makhmour Protection Units, are linked to the PKK. Turkey also claims that its strikes in Makhmour have killed PKK militants (Daily Sabah, June 11).
 See Aaron Stein and Michelle Foley, “The YPG-PKK connection” (Atlantic Council, January 2016).
 While no group claimed the attack, the missile launch pads were found in an area controlled by the PMU’s 30th Brigade.