Commentators are suggesting that the U.S. establish a no-fly zone in Ukraine, and perhaps take even stronger military action, in response to the Russian invasion.  Putting aside the wisdom of those suggestions, the Constitution’s original meaning requires that Congress approve them.

(1) The declare war clause (Art. I, Sec. 8, cl. 11) gives Congress exclusive power over war initiation.  This conclusion arises from the text, founding-era commentary and post-ratification practice.

(a) We may think of a “declaration of war” as a archaic formal announcement of war previously (but no longer) issued before nations engaged in hostilities.  That is not the Constitution’s original meaning, however.  In the eighteenth century, writers routinely referred to “declaring” war by action — most evidently by the use of military force.  (Examples of this use are collected in my article Textualism and War Powers and in this article by Saikrishna Prakash).

In an early example from the seventeenth century, John Locke referred to  “declaring by Word or Action” (Second Treatise on Government, section 16)  And many wars of the time were not formally declared.  An armed attack on another nation itself created a state of war; the attack was as much a declaration as a formal pronouncement would be.  Thus when the Constitution’s text referred to Congress having the power to “declare” war, that included both formal pronouncements (called formal declarations) and acts that initiated a state of war (called declarations by action).

(b) Founding-era commentary described the declare war clause as giving Congress complete power over war initiation, a view shared by key framers Hamilton, Madison, Washington and Wilson, among many others.  For example, Wilson in the Pennsylvania ratifying convention observed: “This system will not hurry us into war; it is calculated to guard against it. It will not be in the power of a single man, or a single body of men, to involve us in such distress; for the important power of declaring war is vested in the legislature at large.”

Hamilton in his 1793 Pacificus essay wrote: “It is the province and duty of the executive to preserve to the nation the blessings of peace. The Legislature alone can interrupt them by placing the nation in a state of war.” And John Marshall in an 1801 case Talbot v. Seeman noted that “the whole powers of war” are “by the constitution of the United States, vested in congress.” (All quoted, along with others, in Textualism and War Powers, pp. 1549-1550).  I’m not aware of anyone in the ratification or early post-ratification period arguing that the President had unilateral war-initiation power.

(c) Early post-ratification practice confirms this allocation.  All of the foreign conflicts in this period were authorized by Congress, notably the 1798 “quasi-war” with France and the 1801 conflict with Tripoli (plus, of course, the War of 1812).  All of the debates surrounding these conflicts assumed that Congress had general control over war initiation.

(2) Congress’ war initiation power included power over limited wars as well as general wars.  A limited war was still understood as a war, as the 1798 quasi-war shows.  In that conflict, Congress approved only limited uses of force against France, principally that the U.S. navy could attack French warships in U.S. waters or on the high seas.  (One might think of it as an eighteenth-century version of a no-fly zone: a no-sail zone).  The conflict’s limited nature led some at the time to call it a “quasi” war.

In the 1800 decision Bas v. Tingy, the U.S. Supreme Court concluded that the conflict with France was indeed a war, notwithstanding its limited nature. And everyone (including Hamilton, the era’s leading advocate of executive power, and then-President Adams) thought the decision to use limited force was within Congress’ exclusive war power.  (For an engaging account of the debates, see David Currie’s The Constitution in Congress: The Federalist Period.)

(3) Undoubtedly some limited uses of military force don’t count as wars, and thus may fall under the President’s independent constitutional powers as commander-in-chief.  But as the quasi-war shows, a sustained use of force against the armed forces of another country counts as a war for constitutional purposes, even if the scope of the force is limited.  The President also likely has constitutional power to respond to attacks on the United States — as Madison said at the 1787 Convention, the President would have power to “repel sudden attacks.”  Presumably that was because the state of war was created by the other country, and the U.S. necessarily would defend itself; thus Congress’ war initiation power wasn’t implicated.

(4) Put together, these points show that under the Constitution’s original meaning, congressional approval is needed for the U.S. to enforce a no-fly zone or otherwise use force to thwart Russia’s attack on Ukraine.  First, using U.S. military force in this way would create a state of war between the U.S. and Russia — it would, in the eighteenth century sense of the phrase, “declare” a war with Russia.  Thus it would fall under Congress’ exclusive war-initiation power.  Second, the fact that the use of force would be limited (to aerial attacks, for example) wouldn’t change the analysis.  A limited war is still a war for constitutional purposes, as the quasi-war shows.  Third, though the President has some independent military powers, they don’t apply in this situation.

In particular, the fact that the U.S. would be defending Ukraine against an attack is immaterial to the constitutional analysis.  (It would presumably make a U.S. military response legal under international law, pursuant to the collective self-defense provisions of Article 51 of the U.N. Charter, but that is a different matter.)  The Russian attack on Ukraine did not create a state of war between Russia and the U.S.  If the U.S. decides to counter the attack on Ukraine with its own attack on Russian forces, the U.S. attack  is what would create a state of war.  And therefore it needs Congress’ approval.

Finally, I think there’s wisdom in the framer’s design here.  A U.S. attack on Russian forces in Ukraine — even a limited one — would be a perilous undertaking.  Whether the risks are justified by the moral and strategic considerations at stake seems a momentous decision best trusted to a deliberative assembly broadly representative of the people.  Congress can act quickly if it wants to, and it has acted quickly on war initiation decisions in the past.

Requiring Congress’ approval does not mean the U.S. won’t be able to use military force; it only means that our recourse to military force may be (somewhat) less hasty than if the decision were left to a single person.

NOTE: This article was originally posted at The Originalism Blog, “The Blog of the Center for the Study of Constitutional Originalism at the University of San Diego School of Law,” and is reposted here with permission from the author.

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