Plaintiffs claim these requirements are met because De- 807 fendants purposefully directed their activi- ties at the United States. Thayer King v. Rvdzewicz, 471 U.S. 4e2, 472, 479, 105 S.Ct. 2174, 85 L.Ed2d 528 (1985) (explain- ing jurisdiction is appropriate if defendant "purposefully directed his act