The case that The New York Times has called “the world’s largest unresolved Holocaust art claim” may provide an answer to that question. In de Csepel v. Republic Of Hungary (10-cv-1261), heirs of the Hungarian banker Baron Mor Lipot Herzog sued in United States District Court in Washington seeking the return of a collection worth more than $100 million. Since the suit is against the Republic of Hungary (and several of its state-run museums, where much of the collection still hangs), the question of foreign sovereign immunity naturally presents itself. The plaintiffs say the doctrine doesn’t apply because the works were taken in violation of international law -- even though it is well-established that a state’s taking of the property of its own citizens cannot violate international law. In a recent decision (issued September 1, 2011), the District Court agreed.