CAATSA can go against Pakistan as it is going against Turkey:
Excerpts:
Mike Pompeo is working to deter Turkey from buying the Russian S-400 air defence system. "The secretary [Pompeo] underscored the seriousness of U.S. concerns...if [the Turkish authorities] go ahead," a senior U.S. State Department official told reporters in Brussels. "He asked Cavusoglu to closely consider NATO interoperable systems."
Pompeo warned the Turks that the Ankara could face sanctions if it when through with the deal. The Turks, however, seem to be undeterred—and struck a defiant tone about the potential infringement upon its sovereignty. “The ‘I will impose sanctions if you buy’ approach will not affect Turkey. Turkey will not accept this. If we are going to discuss what we can do together in the future, we are in,” Turkish Foreign Minister Mevlut Cavusoglu told reporters.