Explicit Waiver of Sovereign Immunity under FSIA: Clarity and Enforceability of Foreign-State Guarantees

1. Introduction

This commentary examines the United States Court of Appeals for the Second Circuit’s decision in Williams v. Federal Government of Nigeria, No. 24-2329 (2d Cir. Apr. 9, 2025). At issue was whether the Federal Government of Nigeria (and its Attorney General), having executed a 1993 “Fidelity Guarantee and Abiding Memorandum of Understanding of Assurance,” explicitly waived sovereign immunity so as to permit enforcement of a UK default judgment in a New York forum under the Foreign Sovereign Immunities Act (FSIA), 28 U.S.C. § 1330 et seq. The plaintiff, Dr. Louis Emovbira Williams, sought to enforce recovery of multi-million-dollar payments allegedly owed under that instrument. After removal to federal court, Nigeria moved to dismiss for lack of subject-matter jurisdiction on grounds of sovereign immunity. The district court denied immunity, the government appealed, and the Second Circuit affirmed.

2. Summary of the Judgment

The Second Circuit affirmed the district court’s order denying the motion to dismiss. Focusing on FSIA § 1605(a)(1), the court held that:

The 1993 Fidelity Guarantee contained clear, unambiguous language waiving “acts of state, state privileges, state secrecy and state immunities” in “any court” (§ 1605(a)(1) exception).
Under Capital Ventures Int’l v. Republic of Argentina, language referring generally to “any court” is sufficient to waive immunity in U.S. federal and state courts, even without explicit reference to the United States.
The district court properly considered extrinsic materials to interpret the waiver language.
The separate 2018 UK judgment ruling that Nigeria had not submitted to UK jurisdiction did not preclude recognition of the waiver under FSIA, because the two proceedings addressed distinct legal questions.

Accordingly, the court held the FSIA exception applied, subject-matter jurisdiction existed, and the default judgment could proceed to enforcement.

3. Analysis

3.1 Precedents Cited

Capital Ventures Int’l v. Republic of Argentina (552 F.3d 289, 293–96 (2d Cir. 2009)) – Held that waiver language in a contract providing for jurisdiction in “any court” suffices to waive FSIA immunity, without needing an express reference to U.S. forums.
Arch Trading Corp. v. Republic of Ecuador (839 F.3d 193, 199 (2d Cir. 2016)) – Confirmed that courts may consider materials beyond the pleadings to resolve FSIA jurisdictional questions.
Pablo Star Ltd. v. Welsh Gov’t (961 F.3d 555, 559 n.5 (2d Cir. 2020)) – Clarified that denials of FSIA immunity are immediately appealable under the collateral order doctrine.
Kensington Int’l Ltd. v. Itoua (505 F.3d 147, 153 (2d Cir. 2007)) – Supported the use of jurisdictional materials outside the complaint when interpreting FSIA exceptions.
Republic of Ecuador v. Chevron Corp. (638 F.3d 384, 400 (2d Cir. 2011)) – Set forth federal common-law principles of issue preclusion, including the requirement of an “identical issue” in two proceedings.
N.L.R.B. v. Thalbo Corp. (171 F.3d 102, 109 (2d Cir. 1999)) – Defined elements of issue preclusion (collateral estoppel) under federal law.

3.2 Legal Reasoning

The court’s reasoning can be divided into two main components:

Waiver of Sovereign Immunity:
- FSIA § 1604 establishes presumptive immunity for foreign states, subject to enumerated exceptions in §§ 1605–1607.
- Section 1605(a)(1) provides an exception where a foreign state “has waived its immunity either explicitly or by implication.” Explicit waiver requires “clear and unambiguous” language (Cap. Ventures Int’l).
- The Fidelity Guarantee’s ¶ 21(1) allowed suit “be it the UK or Nigeria or any other country,” and ¶ 21(3) waived “acts of state, state privileges, state secrecy and state immunities” “without any equivocation and doubt whatsoever.”
- Additional clauses (¶ 18 and ¶ 20) reinforced that neither Central Bank nor the Nigerian State could assert immunity defenses or block execution, and that execution immunity was waived to the extent of the judgment debt.
- These combined provisions satisfied the “clear and unambiguous” standard for an explicit FSIA waiver, thereby permitting U.S. jurisdiction.
Issue Preclusion (Collateral Estoppel):
- The Nigerian defendants argued that a 2018 UK court decision precluded relitigation of waiver because that court held ¶ 21 did not bind the federal government.
- Under federal issue-preclusion rules, four elements must be met, including identity of the issue in both forums (Thalbo; Chevron v. Ecuador).
- The UK court’s examination was limited to whether Nigeria was a party to a “prior agreement” conferring UK jurisdiction—a different question from whether the document contained an explicit waiver of immunity under U.S. law.
- Because the legal issues differed, the district court correctly denied preclusive effect, preserving its independent analysis under FSIA standards.

3.3 Impact

This decision has significant implications for international dispute resolution and enforcement of foreign-state obligations in U.S. courts:

Contract Drafting: Governments and contracting parties will take greater care to include—or avoid—explicit waiver language, knowing that general “any court” phrases will suffice to subject states to U.S. jurisdiction.
FSIA Litigation: Plaintiffs may more readily pursue enforcement of foreign default judgments when they can point to clear waiver provisions, and courts will feel empowered to consider extrinsic evidence in interpreting such waivers.
Forum Choice Clauses: The ruling underscores that broad choice-of-forum language can trigger FSIA exceptions, even absent express mention of U.S. courts.
Preclusion Doctrine: It clarifies that foreign judgments on related but distinct legal questions do not necessarily bind U.S. courts under federal preclusion rules.

4. Complex Concepts Simplified

Foreign Sovereign Immunities Act (FSIA): A U.S. federal statute establishing that foreign states are generally immune from suit in U.S. courts unless an exception applies.
Sovereign Immunity Waiver: A contractual or statutory provision in which a foreign state agrees not to invoke its immunity defenses, thus consenting to suit in a specified forum.
Section 1605(a)(1) Exception: An FSIA carve-out providing that immunity is waived if the state has clearly and unambiguously consented to suit (explicit waiver).
Collateral Order Doctrine: A legal principle allowing immediate appeal of certain interlocutory orders—such as denial of sovereign immunity—rather than requiring final judgment.
Issue Preclusion (Collateral Estoppel): A judicial doctrine barring relitigation of an issue already decided in a prior proceeding, provided the issue is identical, was actually litigated, and was essential to the earlier judgment.

5. Conclusion

The Second Circuit’s affirmation in Williams v. Federal Government of Nigeria cements the principle that explicit, unambiguous waiver language in a foreign-state instrument—even without direct mention of the United States—will strip a sovereign of FSIA immunity. It reinforces the permissive standard for extrinsic evidence in interpreting waivers and clarifies that distinct legal issues in foreign judgments will not automatically foreclose U.S. jurisdiction. As a result, contracting parties and sovereign states must now draft forum-selection and waiver provisions with heightened precision, and litigants can more confidently enforce international agreements in U.S. courts when waiver language is sufficiently clear.