Japan, No. 02 Civ. 10023(DC), 2004 WL 307248, at •2 (S.D.N.Y. Feb. 17, 2004) (citing United States v. S.A. Empresa de Viacao Aerea Rio Grandense Wang Airlines), 467 U.S. 797, 814, 104 S.Ct. 2755, 81 L.Ed.2d 660 (1984) (interpreting FICA)). Generally, acts are discretionary if they are per- formed at the