Key point: With the future of Turkey’s geopolitical orientation hanging in the balance, the Trump administration continues to tread lightly as Washington assesses the likelihood and military consequences of losing Incirlik.

In what may become the latest wedge in Turkey-NATO relations since Ankara’s purchase of the Russian S-400 missile system earlier in 2019, Turkish President Tayyip Erdogan has threatened to shut down the Incirlik air base.

This first appeared in December 2019 and is being reposted due to reader interest.

“If it is necessary for us to take such a step, of course we have the authority ... If this is necessary, together with our delegations, we will close down Incirlik if necessary,” Erdogan told Turkish state television earlier this week.

President Erdogan’s comments were prompted by a recent Senate vote to recognize the early 20th century massacres and mass deportations of Armenians in the Ottoman Empire as a genocide, as well as the ongoing prospect of Ankara’s S-400 deal being sanctioned under the 2017 Countering America’s Adversaries Through Sanctions Act (CAATSA).

Far more than merely a symbolic rift in the U.S.-Turkey defense relationship, the prospective closure of the Incirlik air base forebodes immediate and serious military repercussions for the U.S. The base, located deep in southern Turkey off the mediterranean coastline, houses a 50-unit stockpile of B61 nuclear bombs. A legacy of Cold War-era nuclear deterrence strategy, Incirlik remains the largest U.S. nuclear weapons storage site in Europe. But what used to be a forward post for a retaliatory strike against prospective Soviet encroachment into Western Europe, as well as a crucial bargaining chip during the 1960’s Cuban Missile Crisis, is increasingly seen as a strategic liability amid the stark downturn in U.S.-Turkish relations over the past several years.

Since 1965, Incirlik has also been home to the 39th Air Base Wing (39 ABW). Units from the 39 ABW’s bombardment wing, which today is known as the 39th Tactical Group, played a central role in two of the largest U.S. airpower operations of the past decade: Enduring Freedom and Iraqi Freedom. The U.S. Air Force asserts that as much as 68 percent of all air support for the wars in Iraq and Afghanistan flowed through Incirlik in the early 2000’s.

So, what does the U.S. Air Force stand to lose if forced to pack up and leave Incirlik? First, the opportunity to "pack up" should not be granted as a foregone conclusion; depending on the overarching diplomatic hostility of that divorce if it were ever to happen, the Pentagon cannot discount that Ankara may move to seize some, or all, of the U.S. arsenal in Incirlik.

Barring that catastrophic scenario, the loss of Incirlik would be a major blow to the U.S. capacity to project power in the Middle-East. The U.S. Air Force stands to lose a major logistical support center and refueling site for ongoing its operations in Afghanistan, even as U.S. raids against ISIS and other terrorist targets in neighboring states risk becoming more difficult and expensive. The closure of Incirlik would also weaken US leverage against Iran; though Incirlik was never in the running as a staging post for a strike against Tehran, it is one of several American forward bases for countering the covert activities of the Islamic Revolutionary Guard Corps (IRGC) across the Middle East. 

With the future of Turkey’s geopolitical orientation hanging in the balance, the Trump administration continues to tread lightly as Washington assesses the likelihood and military consequences of losing Incirlik. The White House moved to block the Senate resolution labeling the massacares of Ottoman Armenians a genocide yesterday, calling it "one of the worst mass atrocities of the 20th century" instead. Although the specter of CAATSA continues to loom over Turkey, Washington has dragged its heels on the concern that sanctions would needlessly antagonize Ankara without yielding any Turkish concessions in return.