Foreign states are immune from suit in U.S. courts, unless an exception to immunity provided by the FSIA applies. See 28 U.S.C. §§1604, 1605-1607.2See Argentine Republic v. Amerada Hess Shipping Corp., 488 U.S. 428 (1989).328 U.S.C. §1608(a).4See Republic of Sudan v. Harrison, 587 U.S. ̲ ̲ ̲ (2019). 5Specifically, section 1608 sets out, in hierarchical order, four methods to accomplish service: first, by special arrangement for service between the complainant and the foreign state; second, if no special arrangement is available, then by the rules in an applicable convention on service of judicial documents; third, if service cannot be made under the foregoing two methods, by mail requiring signed receipt to the ministry of foreign affairs; or, fourth, if service cannot be made within 30 days under the third method, then by mail requiring a signed receipt to the Director of Special Counselor Services and through diplomatic channels.
Under the FSIA, a foreign state is immune from the jurisdiction of courts in this country unless one of several enumerated exceptions to immunity applies. 28 U.S.C. §§1604, 1605–1607. If a suit falls within one of these exceptions, FSIA provides for personal jurisdiction “where service has been made under section 1608.”
4 SeeAtkinson v. Inter-American Dev. Bank, 156 F.3d 1335, 1340 (D.C. Cir. 1998), citing letter from Acting Legal Advisor, Dep't of State Jack B. Tate to Attorney General Philip B. Perlman;Jam v. International Finance Corp., 2019 WL 938524, at *3. 5See 28 U.S.C. §§ 1604, 1605(a)(2). 6 Atkinson v. Inter-American Dev. Bank, 156 F.3d 1335 (D.C. Cir. 1998).
Plaintiffs alleged an exception to immunity under the Foreign Sovereign Immunity Act’s (“FSIA”) expropriation exception, which applies, inter alia, to “any case . . . in which rights in property taken in violation of international law are at issue.” 28 U.S.C. §1604. The District Court dismissed in part on jurisdictional grounds, but the D.C. Circuit found that the claim fell within the exception because it was raised in a “nonfrivolous” way.
 See, e.g., Ian Brownlie, Principles of Public International Law 330-32 (5th ed. 1998) (discussing international law of sovereign immunity); 28 U.S.C. §§ 1604, 1609 (establishing default rule of sovereign immunity under U.S. law).  See the relevant sections of the Foreign Sovereign Immunities Act, 28 U.S.C. § 1605A; the Terrorism Risk Insurance Act of 2002, 28 U.S.C. § 1610; and the Iran Threat Reduction and Syria Human Rights Act of 2012, 22 U.S.C. § 8772(b).
Sachs sued OBB in federal court in the Northern District of California. OBB moved to dismiss for lack of subject-matter jurisdiction, arguing that the lawsuit was barred by the Foreign Sovereign Immunities Act, 28 U.S.C. § 1604, which shields foreign states and their agencies and instrumentalities from suit in United States courts. Sachs responded that her lawsuit fell within the FSIA's commercial-activity exception, which withdraws sovereign immunity where "the action is based upon a commercial activity carried on in the United States by [a] foreign state."