Turkey sought to strengthen its air defense system in the face of the ballistic missile threat, and after it did not receive a positive response from the United States regarding its request for the Patriot system, it signed an agreement with Russia in 2017 to purchase the S-400 system worth approximately $2.5 billion.

The first equipment of the system arrived in Turkey in 2019, and was deployed in the command of Murted Air Base in Ankara. The United States responded to the deal by expelling Turkey, a NATO member, from the F-35 fighter manufacturing program in which it was a partner, considering that a NATO member’s possession of a Russian strategic air defense system threatens to weaken the alliance’s joint security structure. It imposed sanctions on it under the CAATSA law, which limited the Turkish Defense Industries Presidency’s access to some defense industry products and financing, and kept 6 F-35 fighters that Turkey paid for in the hangars without Its delivery.

Efforts to find a formula to lift the sanctions accelerated with the improvement of relations between the two countries in the second term of US President Donald Trump, especially after the positive messages that Trump sent about the F-35 during his visit to Ankara, which brought the S-400 file back to the forefront.

Permanently lifting the sanctions imposed on Turkey requires a legislative amendment, which is what the US Congress had previously approved in 2022 for India, which also purchased the S-400 system from Russia. As for temporarily suspending sanctions, it can be done through a presidential exemption mechanism available to the US President, which requires submitting a detailed report to Congress that includes information and concrete developments confirming that Turkey will not use the S-400 system.