F-35 supply chain
Turkey was removed from the list of "global participants" on the official website for the United States' F-35 fighter jets. Turkey's participation in the supply chain was suspended following Ankara's purchase of the Russian S-400 defense system.
Four U.S. senators have penned a letter to Defense Secretary Mark Esper saying that Turkey's expulsion from the F-35 supply chain needs to be expedited, regardless of what the cost is. They said that the Defense Department's delay regarding the matter “has undermined the effectiveness of our clear message to the Turks.”