Presidential War Powers, the Take Care Clause, and Article 2(4) of the U.N. Charter

50 Pages Posted: 27 Jan 2019 Last revised: 9 Oct 2019

Date Written: January 14, 2019


In directing the use of military force without prior congressional authorization, Presidents invoke their authority as “Commander in Chief of the Army and Navy of the United States” under Article II, Section 2 of the Constitution. Examples of such uses of force include the missile strikes directed by President Trump against the Syrian government in 2017 and 2018.

Yet Article II of the Constitution is not only a source of presidential war powers, it also imposes constraints on those same powers. Article II, Section 3 requires that the President “Take Care that the Laws be faithfully executed.” The “Laws” encompass treaties, including the U.N. Charter, which sharply restricts the use of force by States.

This Article argues that by virtue of the Take Care Clause, Article 2(4) of the U.N. Charter binds the President as a matter of domestic law. In substantiating this proposition, this Article relies primarily upon the arguments of the Executive Branch itself in three superficially distinct, though interrelated domains. I demonstrate that the U.S. officials and experts involved in the drafting of the U.N. Charter as well as the senators who provided their advice and consent to the treaty shared an understanding that the Charter would be a “Law” within the meaning of the Take Care Clause. I then show how the President’s duty to execute the Charter was a key element of the Truman Administration’s constitutional justification for directing the Korean “police action” in the absence of prior congressional authorization. By synthesizing Executive Branch views on war powers, the Take Care Clause, and Article 2(4), this Article shows how Presidential arguments advancing claims of authority also delineate the scope of the corresponding constitutional duties.

The Article also rebuts a 1989 Office of Legal Counsel memorandum by now-Attorney General William Barr which concluded that the President may unilaterally “override” Article 2(4) because the treaty provision is non-self-executing and because the use of force is a “political question.” I explain that though the doctrines of non-self-execution and political question may be relevant to the justiciability of Article 2(4) in the courts, neither has any bearing upon the status of Article 2(4) as a “Law” which the President is obligated to faithfully execute.

The conclusion that Article 2(4) is a “Law” has significant implications for the allocation of war powers. Contrary to Barr’s 1989 memo, by virtue of the later-in-time rule, it is Congress, not the President that possesses the authority to “override” this treaty provision.

Keywords: War Powers, U.N. Charter, Jus Ad Bellum, Use of Force, Constitutional Law; Syria; Article 2(4); OLC; Separation of Powers

Suggested Citation

Finucane, Brian, Presidential War Powers, the Take Care Clause, and Article 2(4) of the U.N. Charter (January 14, 2019). Cornell Law Review, Forthcoming, Available at SSRN: or

Brian Finucane (Contact Author)

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