A bipartisan group of senators on April 26 moved to block Nato ally Turkey from receiving F-35 Lightning II fighters over the imprisonment of American pastor Andrew Brunson, The Hill reported. Donald Trump tweeted support for the on-trial Brunson on April 19.

Republican Senators James Lankford and Thom Tillis and Democrat Senator Jeanne Shaheen introduced a bill to prevent the transfer of the Lockheed Martin–made F-35 to Turkey and to block Ankara’s role as a maintenance depot for the aircraft.

Turkey has committed to buying 116 of the F-35A variant of the fighter under the US-led, multinational Joint Strike Fighter program. However, Ankara’s decision to move closer to Moscow geopolitically and place an order for the Russian advanced S-400 missile defence system have already complicated the F-35 acquisition plan. Bne IntelliNews on April 26 drew attention to reports in the trade press on how there are fears that the future maintenance of the UK’s F-35 fighter jets at the Turkish maintenance depot might be put at risk by Washington’s displeasure with Ankara over its planned purchase of the Russian anti-aircraft hardware.  “Uncle Sam has raised the possibility of sanctions against Turkey for buying Russian anti-aircraft missile systems—putting the UK's supply of overhauled F-35 fighter jet engines at risk,” The Register journal noted.

The Netherlands, Italy, Denmark and Norway are the other European countries buying the F-35, and they may be similarly affected by rows between the US and Turkey over the S-400 and the human rights of pastor Brunson.

Lanford reportedly described Turkish President Recep Tayyip Erdogan, who is able to rule by decree under Turkey’s still-in-effect 22-month-long state of emergency, as continuing “down a path of reckless governance and disregard for the rule of law,” meaning the transfer of sensitive F-35 technology to his government would be “increasingly risky”. 

"Turkey’s strategic decisions regrettably fall more and more out of line with, and at times in contrast to, US interests,” he added.

“Furthermore, the Turkish government continues to move closer and closer to Russia, as they hold an innocent American pastor in prison to use him as a pawn in political negotiations. The United States does not reward hostage-taking of American citizens; such action instead will be met with the kind of punitive measures this bill would enact.”

Brunson was jailed 18 months ago after being accused of aiding figures involved in the failed coup 2016 attempt against Erdogan. The Turkish president has lately stated that if the US wants Brunson released it should agree to extradite Fethullah Gulen, the self-exiled elderly cleric whom Ankara holds responsible for organising the attempted putsch, though he strenuously denies any involvement. The US has batted back several requests for his extradition.

Lankford and Shaheen, who both sit on the Senate Appropriations Subcommittee on State, Foreign Operations and Related Programs, last week called for economic sanctions against Turkey if Brunson is not released.