This amicus curiae brief was filed by the Government of Romania in the Supreme Court of the United States in support of the Kingdom of Spain's petition for a writ of certiorari. Romania argues that the Supreme Court should review the D.C. Circuit's decision in NextEra Energy Global Holdings B.V. v. Kingdom of Spain, which held that the arbitration exception to the Foreign Sovereign Immunities Act (FSIA) applies to enforce an arbitral award against a foreign state even where that state did not validly agree to arbitrate the dispute.

Romania contends that the D.C. Circuit's ruling broadens the FSIA's arbitration exception beyond its statutory text and legislative intent, which presuppose the existence of a valid arbitration agreement. The brief highlights that, under binding European Union law as determined by the Court of Justice of the European Union (CJEU) in cases such as Achmea and Komstroy, arbitration agreements for intra-EU investment disputes are invalid. The D.C. Circuit's failure to recognize this principle, Romania argues, infringes upon the sovereignty of EU Member States, disregards principles of international comity, and creates a conflict of laws that could force states like Spain and Romania to violate their EU obligations.

Furthermore, the brief asserts that the D.C. Circuit's decision creates a circuit split with the Second and Fifth Circuits, which require a valid agreement to arbitrate for the FSIA exception to apply. Romania urges the Court to grant certiorari to resolve this split, ensure a uniform application of the FSIA, and prevent U.S. courts from becoming a forum for investors to circumvent the EU's established legal order. The brief emphasizes the importance of the U.S. speaking with "one voice" on matters of foreign sovereign immunity.