Banco Nacional de Cuba v. Sabbatino

In this case, the U.S. District Court acknowledged the Act-of-State doctrine, but the Court nevertheless rendered judgment against the Cuban bank, with the result that the sugar broker did not have to pay the Cuban bank. The basis of the U.S. District Court's decision was that the Act-of-State Doctrine was inapplicable when the act carried out by the state violated international law (in this case, the expropriation of assets of an American citizen without compensation). This decision by the U.S. District Court was reversed by the U.S. Supreme Court.

what do you think was the basis upon which the U.S. Supreme Court found for the Cuban bank (which was owned by the state)?