US Congress mobilises to block Turkey's return to F-35 programme over Russian S-400 system

Trump hints at defence gift ahead of NATO summit

President Donald Trump signalled a potential defence deal with Turkey during a White House meeting with NATO Secretary General Mark Rutte. Asked whether he intended to visit Turkey with a "big bag of gifts" (a reference to Ankara's requests for General Electric engines and F-35 fighter jets), Trump answered affirmatively. The exchange occurred just days before the NATO summit scheduled to take place in Ankara on 7 and 8 July 2026. Vice President JD Vance later confirmed that an official review process is already underway for how such a sale could proceed legally.

Congress launches two-track counteroffensive

In response, Representative Dina Titus, a Democrat from Nevada, is spearheading two separate initiatives. The first is a Joint Resolution of Disapproval to block the sale of F-110 engines to Turkey, which was officially notified to Congress on 24 June, triggering a 15-day window for legislative action under the Arms Export Control Act. The second is a letter to House Majority Leader Steve Scalise and Minority Leader Hakeem Jeffries, collecting signatures and urging them to use section 216(c)(3) of the CAATSA law to file another Joint Resolution if the administration attempts to reinsert Turkey into the F-35 programme without a credible legal basis. A separate bipartisan letter, already sent to Secretary of State Marco Rubio and Defence Secretary Pete Hegseth, warns that the S-400 system "poses an immediate threat to US military aircraft, including F-16 and F-35, allowing Russian intelligence to acquire information on sensitive US technologies if these systems operate side by side."

The S-400 and sanctions barrier

Turkey was removed from the F-35 programme in 2019 after it purchased the Russian S-400 air defence system, and in December 2020 the first Trump administration imposed CAATSA sanctions on Turkey's Presidency of Defence Industries. Those sanctions remain in force, and the lawmakers stress that no public evidence suggests Turkey has removed the S-400 or addressed the reasons for the penalties.

Reintegrating Turkey into the F-35 programme would bring the administration into direct conflict with its own legal obligations.

1. Jul 1, 2019Turkey removed from the F-35 programme after purchasing the Russian S-400 air defence system.
2. Dec 1, 2020First Trump administration imposes CAATSA sanctions on Turkey's Presidency of Defence Industries.
3. Jun 24, 2026US formally notifies Congress of proposed F-110 engine sale to Turkey, opening a 15-day review window under the Arms Export Control Act.
4. Jul 7, 2026NATO summit begins in Ankara; President Trump expected to discuss defence deal including potential F-35 return.

Regional allies and broader concerns

The letter to Rubio and Hegseth also cautions that approving the sale would send a damaging signal to key US partners in the Eastern Mediterranean.

Such a decision would also send the wrong message to America's allies and partners. Key US partners in the Eastern Mediterranean, including Greece, Cyprus and Israel, have consistently aligned with and supported US security interests.

The lawmakers additionally cite Turkey's broader regional conduct, including what they describe as substantial support to Azerbaijan in military operations, as further grounds for excluding Ankara.

What comes next

The 15-day clock on the F-110 engine notification means Congress must act quickly if it is to block that component. A Joint Resolution of Disapproval requires passage by both the House and the Senate, and could still face a presidential veto, making broad and rapid legislative support essential. The parallel CAATSA-based procedure can only be initiated by the Majority or Minority Leader, which the Titus letter says makes it particularly urgent ahead of the 7–8 July NATO summit where Trump may finalise his offer.