. Federal courts must inquire at the “threshold of every action” against a for- eign state whether the exercise of its juris- diction is appropriate. Verlinden B.V. v. Cent. Bank of Nigeria, 461 U.S. 480, 493, 103 S.Ct. 1962, 76 L.Ed.2d 81 (1983). A. Standard of Review [5,6] In a Rule 12(b)() motion to dis- mis