In William Shakespeare's play "Julius Caesar," Cassius, who resolved to assassinate Caesar, asked: "Upon what meat doth this our Caesar feed, that he is grown so great?" Today, the "meat" nourishing the bloated power of the presidency is constitutional theory. The Unitary Executive Theory is a concept that is gradually rising in America's political and judicial debates. This theory contains radical claims, including that the president has the right to unilaterally withdraw from a treaty even if the Senate has consented to it.
Withdrawal from the North Atlantic Treaty Organization (NATO) has emerged as a topic of discussion because of U.S. President Donald Trump's long-held antagonism toward the alliance. This hostility has been amplified recently as some NATO member states have shown uncooperative attitudes regarding the Iran war. Setting aside the question of whether it is wise to leave NATO in the midst of the largest European war since the alliance's founding in 1949, consider the implications of such a claim. It presumes that the president has inherent authority to unilaterally withdraw from any treaty, no matter how consequential.
Saikrishna Bangalore Prakash, a law professor at the University of Virginia, noted on this point: "People often say the Senate ratifies treaties, but the Senate has no such authority. The Senate merely provides 'advice and consent' on the conclusion of treaties." In other words, it consents to the president's ratification process, which is the act of establishing a treaty as both an international contract and domestic law. But an agreement becomes a treaty only with the Senate's consent. And through this, a treaty becomes "the supreme law of the land" as stated in Article VI of the Constitution. If the president unilaterally nullifies a law that he did not create alone, would that not be a violation of the president's duty to "take care that the laws be faithfully executed"?
According to Article 13 of the NATO treaty, any party to the treaty may lose its status as a party one year after giving notice of withdrawal. Then, when the U.S. Congress consented to this treaty in 1949, could it have attached a condition that "the president cannot carry out withdrawal under Article 13 without the consent of Congress"? If it could not, why not? And conversely, if Congress could have asserted such a role then, why not now? Curtis Bradley, a professor at the University of Chicago Law School, points out that "the U.S. Constitution is silent on treaty withdrawal." At the time of the nation's founding, there were only seven treaties. Today, treaties number in the thousands, but none is as important as the NATO treaty.
According to Bradley, for the first 100 years after the founding, no president was thought to have been granted the authority to terminate treaties. Previous presidents cooperated with Congress to terminate treaties. In 2023, 86 senators including Marco Rubio passed legislation, making it current law, stating that "the president cannot suspend, terminate, abrogate, or withdraw the United States from NATO" without a two-thirds Senate vote — the same requirement as for treaty ratification — or an act of Congress. How can a president justify failing to follow this law while simultaneously unilaterally abrogating another law, namely the treaty? The president can unilaterally recognize foreign governments and establish diplomatic relations. But treaties establish the obligations of the United States. The president's primacy in foreign policy does not mean he has the authority to exclude Congress from the process of fulfilling or abrogating these obligations.
Supporters of the Unitary Executive Theory argue that granting executive power to the president means the president monopolizes all authority related to executive duties. John Yoo, a professor at UC Berkeley School of Law, says: "The Constitution only provides for Senate participation in the conclusion of treaties, and therefore all other matters related to international agreements fall under the president's purview." He also argues that "the Senate has no authority to force the president to accept a treaty he opposes." But realistically, no treaty exists that the Senate can unilaterally impose in the first place.
Yoo says "withdrawal from NATO would unquestionably be a foreign policy disaster." Yet his theory emphasizes that in the face of this disaster, the Constitution reduces Congress to a mere bystander. If a theory exhibits such problems, it clearly warrants serious reconsideration.
