The Turkish cabinet formally approved opening the Incirlik air base in southern Turkey on Wednesday to the coalition fighting Islamic State (ISIS). The U.S. has been pressuring Turkey to allow operations from Incirlik for months, but the deadly suicide bombing in the Turkish border town of Suruç last week, and a fatal attack on a soldier three days later, seem to have hardened Ankara’s resolve.

While nominally a part of the coalition, Turkey has been a deeply reluctant participant in the campaign against ISIS until last week. Indeed, Ankara has weathered heavy criticism from the West for turning a blind eye to the group’s activities along Turkey’s border with Syria. While Turkey declared ISIS a terrorist organization last year, it has long downplayed the threat posed by the jihadist group and prioritized the removal of the Bashar al-Assad regime over its defeat.

After a small-scale ISIS attack in March 2014 which killed a police officer and a soldier, Turkey moved to what it called “active defense,” allowing Iraqi Kurdish Peshmerga forces to pass through its territory into Syria to fight ISIS. After the Suruç bombing and the following cross-border shooting, Turkey shifted to what it calls “preemptive defense,” which allows it to strike ISIS targets across the border even before it comes under direct attack. Last week’s bombardment of Jarabulus marked the first such strikes, and was followed by two more sorties against the group. At the same time, the Turkish police conducted over 100 raids nationwide, detaining over 800 suspects including ISIS members.

Closer coordination with the West is now underway. The key to this will be Incirlik, a joint American and Turkish facility built in 1952. The air base is important because of its close proximity to ISIS territory in Syria. Until now, U.S. and coalition aircraft have been forced to fly from air bases in Jordan, Kuwait, Bahrain, Qatar, the United Arab Emirates, and from aircraft carriers in the Persian Gulf. The resulting flight distances – often over 1,200 miles – have a profound effect on operational effectiveness and the cost of sorties. Moreover, with limited time over ISIS territory, pilots must fly more missions to maintain a constant presence to spot and destroy targets or collect intelligence. Finally, combat search and rescue teams have had to fly significantly farther to reach downed pilots deep within ISIS territory, decreasing chances of a successful recovery.

Turkey will now allow a limited number of manned strike aircraft to fly from Incirlik – a dramatic expansion from the two armed Predator drones which it permitted in March, and the logistics and humanitarian missions it already allows. Prior to last week’s announcement, armed coalition aircraft were not even authorized to fly through Turkish airspace, and in one instance last summer, the Turkish air force required a U.S. F-15E that suffered a mechanical problem to be escorted as it flew in and out of the country. It is not clear whether the coalition will be able to use Incirlik to launch search and rescue missions or special operations raids into Syria, but the new agreement grants coalition aircraft access to three Turkish airfields in the southeast for emergency landings.

According to Ankara’s statement on Friday, the Turkish Air Force will join the coalition’s anti-ISIS operations and coordinate its airstrikes. Nonetheless, the coalition’s daily press releases have not yet mentioned Turkey, indicating that Turkish strikes in Syria may not be coordinated with the coalition command but rather aimed at targets Turkey unilaterally chooses.

Turkey also says the coalition will enforce a “safe zone” in a 68-mile wide, 40-mile deep area between Jarabulus and Mare, across the border from the Turkish city of Kilis. While the coalition will provide air cover, the Turkish military will reportedly deploy artillery at the border to target militants within the so-called “ISIS-free zone.” Turkish officials have claimed that the establishment of such an area will necessitate a partial no-fly zone, but the Pentagon insists that no agreement on a no-fly zone has been reached. Such an action would require direct confrontation with Assad’s air force and draw the U.S. deeper into the Syrian civil war.

Moreover, there has been no mention of which forces will clear and protect the area on the ground. While Turkish-backed Syrian rebels are positioned on the western front of the proposed ISIS-free zone, the Kurdish People’s Democratic Union (PYD) and the Syrian regime also are deployed nearby, and could easily take advantage of the bombardment of ISIS fighters to advance into the area. Turkey considers the PYD an equal threat to its territorial integrity as it does ISIS, and has vowed to strike any PYD rebels that enter the zone. Indeed, Turkey conducted two waves of airstrikes against PYD-affiliated militants from the Kurdistan Worker’s Party (PKK) in northern Iraq over the weekend. On Monday, the PYD accused Turkey of striking its militants in Syria as well.

In many cases, Turkish artillery units on the border will require information collected from coalition surveillance aircraft to locate targets. But it is unclear to what degree they will coordinate to that end – the coalition is unlikely to share information of PYD positions with Turkey, thereby causing friction between Ankara and its coalition partners.

Meanwhile, the long-promised U.S.-led plan to train and equip Syrian rebels, which Turkey supports, has progressed at a painfully slow rate, with only 60 fighters having graduated from the program. Developing an effective safe zone without a clear, agreed plan on forces on the ground could put the coalition in direct conflict with Assad’s forces, as well as create a safe haven for extremist rebels like the Nusra Front, al-Qaeda’s affiliate in Syria.

Turkey’s active involvement in the war against ISIS and the opening of Incirlik to the coalition will be a net positive. However, one key question remains: How committed is Turkey to the defeat of the Islamic State? Thus far, Ankara appears to be more interested in containing the PYD, which is currently the coalition’s most reliable ally on the ground.

Merve Tahiroglu is a research analyst at Foundation for Defense of Democracies, where Patrick Megahan is a research analyst and manages