Explicit Waiver of Sovereign Immunity Under FSIA: Clear and Unambiguous “Any Court” Clause Suffices

1. Introduction

In Williams v. Federal Government of Nigeria (2d Cir. Apr. 9, 2025), the Second Circuit addressed whether a foreign sovereign entity had explicitly waived its immunity under the Foreign Sovereign Immunities Act (FSIA) by agreeing in a 1993 instrument—the “Fidelity Guarantee and Abiding Memorandum of Understanding of Assurance”—to submit any enforcement proceedings “be it the UK or Nigeria or any other country.” The plaintiff, Dr. Louis Emovbira Williams, sought to enforce a UK default judgment against the Nigerian State and its Central Bank for unpaid sums. The Federal Government of Nigeria and its Attorney General removed the suit to federal court in New York and moved to dismiss for lack of subject-matter jurisdiction, invoking sovereign immunity. The district court denied the motion, finding an explicit waiver of immunity; the defendants appealed.

2. Summary of the Judgment

The Second Circuit affirmed. It held that:

Paragraph 21 of the Fidelity Guarantee contained a “clear and unambiguous” waiver of sovereign immunity under 28 U.S.C. § 1605(a)(1). The language conferring jurisdiction in “any country” encompassed U.S. federal and state courts.
Additional provisions (paragraphs 18 and 20) reinforced that Nigeria and its Central Bank “shall refrain from raising any objection on grounds of state immunities” and “are deemed to have waived any immunity from levying execution.”
The UK default judgment’s holding that Nigeria had not consented to UK jurisdiction did not preclude the U.S. court from interpreting the contract under FSIA waiver standards, because the two proceedings turned on different legal issues.

Consequently, the district court retained subject-matter jurisdiction and correctly denied the motion to dismiss.

3. Analysis

3.1 Precedents Cited

Capital Ventures Int’l v. Republic of Argentina, 552 F.3d 289 (2d Cir. 2009): Held that a waiver of immunity in “any court” is a sufficiently explicit waiver under FSIA. The panel here applied the same standard of clarity and unambiguity.
Arch Trading Corp. v. Republic of Ecuador, 839 F.3d 193 (2d Cir. 2016): Authorized courts to consider extrinsic evidence outside the pleadings when assessing FSIA jurisdictional exceptions.
Kensington Int’l Ltd. v. Itoua, 505 F.3d 147 (2d Cir. 2007): Confirmed that a foreign state’s invocation of FSIA immunity turns on contractual language rather than formal diplomatic instruments.
Pablo Star Ltd. v. Welsh Gov., 961 F.3d 555 (2d Cir. 2020): Clarified that denials of immunity under FSIA are immediately appealable under the collateral order doctrine.
Republic of Ecuador v. Chevron Corp., 638 F.3d 384 (2d Cir. 2011): Established federal issue-preclusion principles (collateral estoppel) in the context of foreign sovereign litigation.

3.2 Legal Reasoning

The court’s reasoning rested on two pillars:

Explicit Waiver Under FSIA § 1605(a)(1): FSIA provides that a foreign state is immune from suit unless it has waived immunity “explicitly.” Adopting the “clear and unambiguous” standard from Capital Ventures, the court found that the Fidelity Guarantee’s commitment to litigate “in any country” leaves no doubt that Nigeria consented to U.S. jurisdiction. Paragraphs 18 and 20 further confirm waivers of defenses and execution immunities.
Issue Preclusion and the UK Judgment: Defendants argued that the 2018 UK decision, which held that Nigeria had not agreed to UK jurisdiction, should estop the U.S. court from finding a waiver. Under federal collateral-estoppel doctrine, an issue must be identical in both proceedings to be preclusive. Here, the UK court focused on whether the sovereign itself signed the contract, whereas the U.S. court focused on whether the contract language, irrespective of signatory formality, waived immunity under FSIA. Because these issues diverged, preclusion did not apply.

3.3 Impact

This decision sharpens the rule for FSIA waivers:

Foreign states must use clear, unambiguous language—such as consent to suit “in any court”—to waive immunity, and such language will be enforced in U.S. federal and state courts.
Litigants relying on contractual waivers of immunity can look beyond the formal signatories and emphasize waiver clauses in related instruments.
It limits the preclusive effect of foreign judgments when they address different legal questions, ensuring U.S. courts retain the authority to interpret FSIA waivers under domestic standards.
Future defendants will need to craft waivers with precision or risk subject-matter jurisdiction in U.S. litigation.

4. Complex Concepts Simplified

Foreign Sovereign Immunities Act (FSIA): A federal statute that sets the default rule that foreign states are immune from U.S. court suits unless a statutory exception (e.g., waiver) applies.
Explicit Waiver: A foreign state’s clear, unambiguous contract language consenting to suit in U.S. courts. Must be sharper than vague or implied expressions.
Collateral Estoppel (Issue Preclusion): A doctrine barring relitigation of an issue that was already decided in a prior case between the same parties—provided the issue is identical, was actually litigated, and the decision was necessary to the outcome.
Collateral Order Doctrine: Allows immediate appeal of certain trial court orders, such as denial of sovereign immunity, even if the case has not reached final judgment.

5. Conclusion

Williams v. Federal Government of Nigeria establishes that under FSIA § 1605(a)(1), a waiver of sovereign immunity in “any court” is sufficiently explicit to confer U.S. jurisdiction. The decision reinforces that waiver clauses must be clear and unambiguous, and it underscores that foreign judgments do not automatically bind U.S. courts when they hinge on different legal inquiries. This ruling will guide future litigants and states in drafting enforceable immunity waivers and clarifying jurisdictional consent under international instruments.