Note: Banco Nacional de Cuba v. Sabbatino
According to Gary Born, International Civil Litigation in U.S. Courts (3d ed, 1996), at 688, Sabbatino relied in significant part on domestic separation of powers considerations.
Justice Harlan, writing for the majority in Banco Nacional de Cuba v. Sabbatino, 376 U.S. 398, 423, 425 (1964), noted that the “constitutional underpinnings” of the Act of State Doctrine reflect “a basic choice regarding the competence and function of the Judiciary and the National Executive in ordering our relationships with other members of the international community.”If Congress tried to eliminate the Act of State Doctrine, I would expect the law to be challenged on domestic constitutional grounds the first chance anyone had to raise the issue
