Trump cannot lift Turkey sanctions without Congress, expert warns

President Donald Trump cannot lift Turkey’s sanctions on his own, because Congress already embedded the punishment into law after Ankara bought Russia’s S-400 missile defense system, University of Chicago professor Paul Poast warned. The case has become a sharp test of separation of powers: presidents can often impose sanctions quickly, but Congress can make them far harder to unwind once lawmakers codify them with bipartisan backing.

Turkey accepted the Russian-made S-400 in July 2019, and the United States removed Ankara from the F-35 Joint Strike Fighter program on July 17, 2019. Congress later tightened the restrictions in Section 1245 of the Fiscal Year 2020 National Defense Authorization Act, Public Law 116-92, enacted on Dec. 20, 2019, which limits any transfer of F-35 aircraft to Turkey unless strict certification conditions are met. The Pentagon has said Turkey cannot have both the Russian system and the fifth-generation fighter.

The sanctions under the Countering America’s Adversaries Through Sanctions Act were imposed in 2020 over the S-400 purchase, adding a second layer of pressure on Ankara. The Defense Department said it was unwinding Turkey from the F-35 program because of the Russian buy, and Turkey lost its production work on the jet by March 2020. Ankara has rejected its removal from the program as unfair and said the U.S. decision lacked justification.

The legal and political architecture now matters as much as the bilateral dispute itself. Hakan Fidan, Turkey’s foreign minister, said on July 2, 2026, that political will exists on both sides to lift CAATSA sanctions and that technical steps were underway. But congressional opposition to Turkey’s return to the F-35 program has stayed bipartisan, with lawmakers in recent months warning the White House against readmitting Turkey and insisting that Congress has consistently supported both the sanctions and Ankara’s exclusion.

That makes Turkey more than a NATO spat. It is a live example of how Congress can constrain White House diplomacy long after a president changes course, and a warning sign for future sanctions fights where foreign policy, defense procurement and legislative power collide.