Jordan Paust [University of Houston Law Center]: "Recent litigation re: GTMO detainees in a Circuit Court has raised the issue whether the 2001 Authorization for Use of Military Force (AUMF) is relevant to requirements of the 1949 Geneva Conventions that provide detainee rights and Executive duties. As noted in a previous JURIST Forum essay, Not Authorized By Law: Domestic Spying and Congressional Consent (Dec. 2005):

The word 'appropriate' [in the AUMF] creates a statutory limitation that necessarily requires Executive compliance with relevant constitutional, international, and other federal laws, especially since Supreme Court opinions have long recognized that relevant international law and prior federal statutes are a necessary background more generally for interpretation of newer federal statutes.

Indeed, under Article II, Section 3 of our Constitution the President has an express and unavoidable duty to faithfully execute the 'Laws' and has no power to violate them. As Richard Nixon learned, presidential authorizations to violate the law are, in the words of the House Judiciary Committee, 'subversive of constitutional government.' Additionally, since 1800 Supreme Court opinions have recognized the power of Congress to limit certain Commander in Chief powers during actual war (see, e.g., 43 Columbia J. Transnat'l L. 811, 842 n.114 (2005)….

Quite clearly, in the AUMF Congress has limited presidential authority to act merely in "appropriate" ways and it would be most inappropriate for the Executive to attempt to authorize, order, abet, condone, etc., violations of customary or treaty-based international law since the President is bound by and must faithfully execute international law. See, e.g., 43 Columbia J., supra at 856-61; Jordan J. Paust, International Law as Law of the United States 7-11, 169-73, 180-87 nn.2-42, 489-90, 493-95, 499-502 nn.23-31, 507-10 nn.82-103 (2 ed. 2003)."