Last week, the Pentagon shared a classified report with Congress regarding the benefits and negatives of removing Turkey from the F-35 Joint-Strike Fighter production and acquisition program. Now, it’s time for American lawmakers to decide what happens.

Turkey is scheduled to receive the initial bunch of F-35s in the summer of 2019. Opponents of the sale, however, hope that additional training for the Turkish pilots could delay deliveries till 2020. Moreover, they can hope that Congress will try to block the transfer of classified technology, such as the aircraft’s battlespace management system, a decision that would further frustrate the delivery schedule. The Turkish Air Force has already received two jets and is vying to get at least 100.

Earlier this year, Defence Secretary James Mattis had warned Congress that “If the Turkish supply chain was disrupted today, it would result in an aircraft production break, delaying delivery of 50-75 F-35s, and would take approximately 18-24 months to re-source parts and recover.”

Turkey recently purchased a number of Russian S-400 anti-aircraft batteries at an estimated $2.5 billion. Pentagon officials are concerned that the purchase, coupled with the introduction of the F-35 to the Turkish Air Force, will enable Russian engineers to break the F-35’s stealth capabilities and find a way to update the S-400’s radar to detect America’s latest — and most expensive — aircraft.

If Congress decided to oust Turkey from the F-35 program, the U.S. government would have to reimburse Turkey and then decide if it or another partner would undertake Turkey’s production part, which is mainly concerned with the F-35’s fuselage.

Some geopolitical background, however, is essential. What can Turkey offer to the U.S.? A nuclear-capable base and, perhaps, a helping hand in the Syrian conflict. The Incirlik Air Base in South-central Turkey has long been an important strategic base for the U.S. military. Containing an estimated 50 nuclear warheads, the base is close — but not so close to jeopardise security — to many major countries in the Middle East. Syria, Iraq, Lebanon, and even Iran, are within reasonable distance from the base.

The American military has used (or tried to use) the base before for major operations. During the ramping up of Operation Iraqi Freedom in 2003, Turkey famously denied access or transit to U.S. troops that were to invade northern Iraq. In the end, a handful of Special Forces teams from the 10th Special Forces Group and Special Boat Service (SBS), alongside Kurdish militia, managed to do what was supposed to be the job of whole divisions — revealing that Turkey’s importance isn’t so large as many would have it be.

Congress will now have to study the Pentagon’s report before scheduling a briefing with Secretary Mattis and other senior Department of Defence (DoD) officials to decide what will be done.