ANKARA, Turkey—U.S. President Donald Trump announced on July 7 that he is working to lift sanctions preventing Turkey from obtaining F-35 Lightning II stealth fighter jets. Turkey was an early partner on the F-35 program but was barred from obtaining the advanced aircraft after purchasing Russian S-400 air defense systems in 2019. These S-400 purchases ran afoul of the 2017 Countering America’s Adversaries Through Sanctions Act. “We’re going to be taking the sanctions off,” Trump told reporters, following a meeting with Turkish President Recep Tayyip Erdogan in Ankara on July 7. “It’s time to do that.” Reversing sanctions will require multiple steps. A provision of the 2020 National Defense Authorization Act requires the secretaries of state and war to certify that Turkey’s military no longer operates the S-400 and has offered assurances that it will not accept such Russian air defense systems before it can begin receiving F-35s....