Procedural Posture and Purpose

This document is an amicus curiae brief filed by the European Commission, on behalf of the European Union, before the Supreme Court of the United States. The brief is submitted in support of the Kingdom of Spain's petition for a writ of certiorari to the U.S. Court of Appeals for the District of Columbia Circuit. The underlying dispute concerns the enforcement of arbitral awards obtained by EU investors against Spain under the Energy Charter Treaty (ECT).

Key Arguments of the Amicus Curiae

The European Commission argues that the case presents issues of exceptional importance to the European Union's legal order and that the D.C. Circuit's decision warrants review. The core of the Commission's position is that intra-EU investment arbitration is fundamentally incompatible with EU law. Citing binding precedent from the Court of Justice of the European Union (CJEU), particularly the *Achmea* and *Komstroy* judgments, the brief asserts that EU Member States cannot, and did not, consent to arbitrate investment disputes with investors from other EU Member States under the ECT. Consequently, Spain never made a valid offer to arbitrate, and no valid arbitration agreement was ever formed with the respondent investors. The Commission contends that the D.C. Circuit erred by treating the existence of a valid arbitration agreement as a merits question rather than a threshold jurisdictional requirement under the Foreign Sovereign Immunities Act (FSIA).

The brief further argues that the D.C. Circuit's decision encourages the enforcement of intra-EU awards in the United States, even though such awards are invalid and unenforceable within the entire EU. This outcome undermines the integrity of the EU's autonomous legal system, which requires that disputes involving EU law be resolved within the EU's judicial framework, under the ultimate authority of the CJEU. The decision invites a "deluge" of enforcement actions in U.S. courts, creating conflicts with EU law, particularly concerning State aid rules, which may prohibit the payment of such awards without prior Commission approval.

Broader Implications and Relief Sought

Finally, the Commission warns that the D.C. Circuit's reasoning has broad repercussions beyond the immediate case. By holding that an investment treaty itself can constitute a completed agreement to arbitrate sufficient to abrogate sovereign immunity under the FSIA, the decision potentially affects hundreds of modern investment treaties and exposes numerous foreign sovereigns to litigation in U.S. courts. The European Commission urges the Supreme Court to grant the petition for certiorari to address these critical questions of international comity, sovereign immunity, and the proper interpretation of the FSIA's arbitration exception.