Doubtless Congress, by virtue of its powers in the field of foreign relations, might also lay down a mandatory rule regarding recognition of foreign judgments in every court of the United States. At present the duty to recognize judgments even in national courts rests only on comity and is qualified in the judgment of the Supreme Court, by a strict rule of parity. 146
[Footnote 146] No right, privilege, or immunity is conferred by the Constitution in respect to judgments of foreign states and nations. Aetna Life Insurance Co. v. Tremblay, 223 U.S. 185 (1912). See also Hilton v. Guyot, 159 U.S. 113, 234 (1895), where a French judgment offered in defense was held not a bar to the suit. Four Justices dissented on the ground that ''the application of the doctrine of res judicata does not rest in discretion; and it is for the Government, and not for its courts, to adopt the principle of retorsion, if deemed under any circumstances desirable or necessary.'' At the same sitting of the Court, an action in a United States circuit court on a Canadian judgment was sustained on the same ground of reciprocity, Ritchie v. McMullen, 159 U.S. 235 (1895). See also Ingenohl v. Olsen & Co., 273 U.S. 541 (1927), where a decision of the Supreme Court of the Philippine Islands was reversed for refusal to enforce a judgment of the Supreme Court of the British colony of Hong Kong, which was rendered ''after a fair trial by a court having jurisdiction of the parties.'' Another instance of international cooperation in the judicial field is furnished by letters rogatory. See 28 U.S.C. Sec. 1781. Several States have similar provisions, 2 J. Moore, Digest of International Law (Washington: 1906), 108-109.