The Declare War Clause

The Congress shall have Power . . . To declare War. . . .

—John C. Yoo

Introduction

Few constitutional issues have been debated so consistently and heatedly by legal scholars and politicians as the distribution of war powers between Congress and the President. As a matter of history and policy, it is generally accepted that the executive takes the lead in the actual conduct of war. A single, energetic actor is better able to prosecute war successfully than a committee is: The enemy will not wait for deliberation and consensus. At the same time, the Founders plainly intended to establish congressional checks on the executive’s war power. Between these guideposts is a question of considerable importance: Does the Constitution require the President to obtain specific authorization from Congress before initiating hostilities?

History Before 1787

Well before American independence, jurists had discussed the significance of declaring war. In 1625, Grotius explained that declarations of war gave notice of the legal grounds for the war and the opportunity for enemy nations to make amends.¹ These declarations also served notice on the enemy’s allies that they would be regarded as cobelligerents and their shipping would be subject to capture.² Grotius added that declarations of war triggered such legal actions as the internment or expulsion of enemy aliens, breaking of diplomatic relations, and confiscation of the enemy’s property.³ In 1758, Vattel wrote that “when one nation takes up arms against another, she from that moment declares herself an enemy to all the individuals of the latter.”⁴ Vattel explained that when a country declares war, its navy and privateers could not be treated as pirates by the enemy, but its citizens were subject to prosecution if they dealt with the enemy.⁵

Sir William Blackstone agreed with these writers of international law. He described two purposes for a declaration of war in Britain: It notified other nations that the state approved the hostilities, and it legally bound the citizens to the king’s decision to wage war.⁶ Blackstone also contemplated an “incomplete state of hostilities”—hostilities before or without a formal declaration of war.⁷

During this time, the British monarch, not Parliament, had the power to declare war.⁸ Many contemporary thinkers understood the executive power to arise from the need for a part of government to act quickly, vigorously, and decisively in response to unforeseen dangers and events, the most serious being war. John Locke described the executive as a “power always in being,” bearing the responsibility to “see to the execution of the laws that are made.”⁹ Montesquieu explained that the executive power “makes peace or war, sends or receives embassies, establishes the public security, and provides against invasions.”¹⁰ Blackstone thought that “[i]t would indeed be extremely improper, that any number of subjects should have the power of binding the supreme magistrate, and putting him against his will in a state of war.”¹¹ A single executive should have this power.

In April 1775, hostilities broke out between British forces and the Americans at Lexington and Concord, but war was not declared immediately.¹² It was not until nearly a year later that the Continental Congress issued the Declaration of Independence, a formal declaration of war against Great Britain that asserted the “full Power to levy War, [and] conclude Peace.”¹³

The Articles of Confederation gave Congress “the sole and exclusive right and power of determining on peace and war.”¹⁴ The Articles required the approval of nine states before the nation could “engage in a war.”¹⁵ They further provided that no state “shall . . . grant commissions to any ships or vessels of war, nor letters of marque or reprisal, except [if] it be after a declaration of war by the united states in congress assembled.”¹⁶ This text suggests that the power to declare war was understood to be a subset of the power to make war.¹⁷

The Constitutional Convention

An early Committee of Detail draft in the handwriting of Edmund Randolph of Virginia granted Congress the power “[t]o make war” alongside the power to “raise armies.”¹⁸ The Committee of Detail’s report was delivered to the Convention on August 6.¹⁹ Congress would have the power “[t]o make war; [t]o raise armies; [and] to build and equip fleets.”²⁰ The delegates debated this provision on August 17.

James Madison of Virginia and Elbridge Gerry of Massachusetts moved to replace “make war” with “declare war” and “leav[e] to the Executive the power to repel sudden attacks.”²¹ Roger Sherman of Connecticut favored “make” over “declare,” as the “latter narrow[ed] the power too much.” He thought the Executive should “be able to repel and not to commence war.”²² Gerry responded that he “never expected to hear in a republic a motion to empower the Executive alone to declare war.”²³ George Mason of Virginia “preferred ‘declare’ to ‘make’” as a means to “clog[] rather than facilitate war.”²⁴ Madison’s and Gerry’s motion passed by a vote of 7 to 2 with one state absent.

On September 5, the Committee of Eleven proposed that the “declare war” clause should be amended to give Congress the power to “grant letters of marque and reprisal.”²⁵ The proposal passed without debate. The Declare War Clause was then referred to the Committee of Style.²⁶ The Committee’s report lumped together three separate powers: “[t]o declare war, grant letters of marque and reprisal, and make rules concerning captures on land and water.”²⁷ Article I, Section 8, Clause 11 received no further edits.

Certain inferences can be drawn from the text of the Declare War Clause. First, Article I, Section 8, Clause 11 enumerates three specific powers: “[t]o declare War, grant Letters of Marque and Reprisal, and make Rules concerning Captures on Land and Water.” If the power to “declare War” included the broad authority to authorize and define the boundaries of any military conflict, then there would be no reason to enumerate the lesser powers. The Marque and Reprisal Clause and the Capture Clause, as well as other provisions, would be redundant, inconsistent, or superfluous. (See Essay Nos. 57 and 58.) But if the Declare War Clause only gives Congress the power to define the legal state of relations with hostile countries, this arrangement makes perfect sense.²⁸ These other powers are useful in defining the legal rules of hostilities that fall short of being a major declared war.

Second, the Constitution forbids states from “engag[ing] in” war without the consent of Congress.²⁹ (See Essay No. 86.) This provision would suggest a difference between starting a war and declaring a war. The Constitution further provides that a state may “engage in War” if it is “actually invaded, or in such imminent Danger as will not admit of delay.”³⁰ This text suggests that a state can start new hostilities if attacked even without seeking congressional approval. In other words, a state’s power to “engage in war” includes the power to defend itself. It is generally agreed that the President may authorize hostilities without congressional action if the war is defensive. Yet Article I, Section 8 does not give Congress the power to “engage in war.” It provides the power to “declare war,” and with this narrow phrasing, there was no need to provide that the President has the power to use self-defense to repel an invasion.

Third, the Constitution uses different language to refer to powers of Congress and the powers of the President. Article I, Section 8 appears to be an explicit enumeration of Congress’s limited powers, while Article II, Section 2 vests in the President a broad grant of authority as “Commander in Chief” of the Army, Navy, and Militia. As between Congress and the President, the grant of authority in Article II may imply that the Executive retains the larger portion of the war power.³¹

The Ratification Debates

During the ratification process, there were extensive debates about the relationship between Congress and the President with respect to war powers. In Federalist No. 70, Alexander Hamilton stressed that “[g]ood government” requires “energy in the executive” and that “in the conduct of war, in which the energy of the Executive is the bulwark of the national security, every thing would be to be apprehended from its plurality.” But there were limits to that energy. In Federalist No. 69, Hamilton distinguished between the British king’s powers and the President’s executive powers. In Britain, the king had the power to declare war, and Parliament had the power to raise armies; Article I granted Congress both the power to declare war and the power to raise armies. Hamilton also recognized that there were undeclared wars in Britain. In Federalist No. 25, he observed that “the ceremony of a formal denunciation of war has of late fallen into disuse.”

The Anti-Federalists criticized the Declare War Clause for “concentrating power in Congress.”³² For example, an Anti-Federalist from Pennsylvania observed that in England, “the king has only the power of declaring war, and the house of parliament, that of raising money for the support of it.”³³ The Federal Republican wrote “that it seems to be wrong to give Congress this combined power independent of a check from a majority of the state legislatures.”³⁴

Patrick Henry made a similar point in the Virginia ratifying convention. Henry favored the British system in which the king’s power to declare war was separated from Parliament’s power to raise armies. He warned that “The Congress can both declare war, and carry it on; and levy your money, as long as you have a shilling to pay.”³⁵ Yet Henry also warned that the President would use his army domestically to “enslav[e] America.”³⁶ Scholars have debated how to reconcile these Anti-Federalist arguments.³⁷

Madison responded that “the sword and purse are not to be given to the same member.” Rather, in America, the President, like the king, has the sword, and Congress, like Parliament, has the purse.³⁸ Here, Madison did not seem to think the power of the sword was equivalent to the power to declare war. For example, he later explained in a letter to Thomas Jefferson that “the Executive is the branch of power most interested in war, and most prone to it.” Madison observed that the Constitution “has accordingly with studied care, vested the question of war in the Legisl[ature].”³⁹

Practice Before 1973

In the early Republic, Congress affirmatively authorized numerous conflicts with formal declarations of war and other instruments. There was broad consensus that such authorizations were constitutionally required in the case of offensive war. In the Quasi-War of 1798 with France, Congress authorized a naval conflict and also carefully regulated how America’s ships would carry out that conflict.⁴⁰ In 1801, the first real war began against Tripoli. Congress authorized this conflict by statute, but there was no formal declaration.⁴¹ President Thomas Jefferson arguably directed some offensive action against Tripoli prior to congressional authorization.

Hamilton defended these actions only on the ground that Tripoli had itself begun the war: “[W]hen a foreign nation declares or openly and avowedly makes war upon the United States, they are then by the very fact already at war, and any declaration on the part of Congress is nugatory; it is at least unnecessary.”⁴² Several years earlier, Hamilton had acknowledged Congress’s role in a Pacificus essay: “It is the province and duty of the executive to preserve to the nation the blessings of peace,” but “[t]he Legislature alone can interrupt them by placing the nation in a state of war.”⁴³

Since ratification of the Constitution, only five wars have been formally declared by Congress.⁴⁴ The War of 1812 was formally declared before the start of hostilities.⁴⁵ However, in four other conflicts, Congress merely declared the prior existence of a state of war: the Mexican-American War of 1846, the Spanish-American War of 1898, World War I, and World War II.⁴⁶ Each of these declarations was accompanied by an express authorization for the use of force. During these conflicts, limited budgets and a small peacetime military led Presidents to defer to Congress.⁴⁷ If the Presidents wanted to wage a war, they had to ask Congress to build them the armed forces to fight it.⁴⁸ Congress has not issued a formal declaration of war since 1942.

After World War II, the creation of a large standing military dramatically altered the balance of war powers between the two branches.⁴⁹ Modern Presidents have been more aggressive in asserting unilateral authority to use force abroad without a declaration of war or other congressional authorization. The United States intervention in Korea in 1950 received congressional support but no formal approval.⁵⁰ President Harry S. Truman claimed independent authority to commit troops without congressional authorization because the United Nations Security Council had authorized U.N. members to use force in resisting the North Korean invasion.⁵¹

Congress also did not declare war in Vietnam.⁵² Presidents Lyndon B. Johnson and Richard M. Nixon undertook military operations in Vietnam armed only with the vaguely worded congressional approval in the Gulf of Tonkin Resolution.⁵³ Congress ended U.S. involvement in Vietnam by passing funding restrictions in 1973 rather than merely ending the war by fiat.⁵⁴

Practice After 1973

In 1973, Congress enacted the War Powers Resolution over President Nixon’s veto.⁵⁵ The statute purports to limit the President’s ability to engage U.S. forces in hostilities for more than sixty days without a declaration of war or specific congressional authorization. The law also requires the President to consult with Congress about military deployments. No President has ever conceded its constitutionality, although many have acted “consistent with” its sixty-day limit on foreign interventions.⁵⁶ Presidents have unilaterally authorized military action in Iran, Lebanon, Grenada, Libya, Somalia, Bosnia, Haiti, Kosovo, Afghanistan, and Iraq.⁵⁷

President Jimmy Carter did not consult with Congress before attempting to rescue Iranian hostages.⁵⁸ President Ronald Reagan unilaterally dispatched American military forces to Lebanon, Grenada, Libya, and the Persian Gulf.⁵⁹ Before Operation Desert Storm, President George H.W. Bush sent reports to Congress in which he failed to acknowledge that he had to consult with Congress or had to remove the troops in sixty days.⁶⁰ Bush nevertheless sought an authorization from Congress that he barely received.⁶¹ President William Jefferson Clinton followed these precedents in Somalia, Haiti, Bosnia, the Middle East, and Kosovo.⁶²

On September 18, 2001, Congress authorized the use of military force against those who were responsible for the 9/11 terrorist attacks. President George W. Bush used this authority to engage in hostilities against Al-Qaeda in Afghanistan. In 2002, Congress authorized the use of military force against Iraq. President Bush used this authority to topple Saddam Hussein’s government. In 2011, President Barack Obama unilaterally ordered an intervention in the Libyan civil war. Obama contended that these hostilities, which did not include ground troops, were too small to constitute a “war” under the Constitution.⁶³

During President Donald Trump’s first term, he continued the war against the Islamic State of Iraq and Syria (ISIS) and loosened the rules of engagement to allow U.S. forces to fight more aggressively.⁶⁴ Trump also invoked executive constitutional authority for multiple strikes against Syria.65 One of those strikes killed Iranian General Qassem Soleimani.⁶⁵ In 2018, the Office of Legal Counsel (OLC) opined that the Constitution gives the President “the authority to direct U.S. military forces in engagements necessary to advance American national interests abroad.”⁶⁶ OLC recognized that Presidents have authorized many hostilities abroad, but only Congress may commit the United States to a war in the constitutional sense. OLC concluded that attacking Syria did not rise to the level of a war because of the “anticipated nature, scope, and duration” of the conflict.⁶⁷ To be a war, a conflict must be “characterized by ‘prolonged and substantial military engagements.’”⁶⁸ OLC grounded this position in past executive branch opinions dating from the Nixon Administration through the Obama Administration as well as authorities stretching back to the Framing. The text of the Constitution, however, does not suggest a definition of war based on the magnitude of the conflict or the potential for harm to U.S. forces. Under this standard, would a nuclear attack qualify as a war because it does not risk any U.S. troops and does not involve a “prolonged” engagement?

President Joseph R. Biden, relying on this authority, directed targeted airstrikes in Syria without seeking permission from Congress.⁶⁹ In 2022, following Russia’s invasion of Ukraine, Biden deployed thousands of troops to Poland, Germany, and other nations. Biden cited the United States’s NATO obligations, but pledged that the U.S. would not take part in the conflict directly.⁷⁰

Judicial Precedent

The U.S. Supreme Court has never intervened to stop a war regardless of whether Congress had authorized it. The Prize Cases (1863) stated in dicta that the President “has no power to initiate or declare a war.”⁷¹ This decision upheld President Abraham Lincoln’s military actions against the Confederacy that occurred before congressional authorization. The Court reasoned that “the President is not only authorized but bound to resist force by force . . . without waiting for any special legislative authority.”⁷²

Some federal courts have held or implied that at least some level of congressional authorization is constitutionally required before the President may conduct military hostilities. Orlando v. Laird (1971), for example, ruled that “the test is whether there is any action by Congress sufficient to authorize or ratify the military activity in question.”⁷³ Other courts have found that the issue was not subject to review by the courts.⁷⁴

Members of Congress and private citizens have periodically filed suit to enforce the War Powers Resolution, but the lower courts have generally avoided ruling on the merits of these cases. Instead, these cases were dismissed on procedural grounds. In Campbell v. Clinton (2000), the D.C. Circuit unanimously dismissed a challenge to President Clinton’s airstrike campaign in the former Yugoslavia because members of Congress did not suffer a legally cognizable injury.⁷⁵ In O’Connor v. United States (2003), the Tenth Circuit dismissed a citizen’s challenge to the war in Iraq.⁷⁶ The court reasoned that this case posed a political question and that “there are no judicially discoverable standards that would permit a court to determine whether the intentions of the President in prosecuting a war are proper.”⁷⁷

Scholarly Debates

In modern scholarly debates, there are two general views about the Declare War Clause. Under the Congressional View, the clause requires congressional authorization of hostilities, which may be done by formal declaration or otherwise.⁷⁸ In other words, only Congress can decide whether and when the United States will initiate hostilities against a foreign power. Since Congress has the power to declare war, it has the sole power to initiate hostilities. War must occur within a legalistic, step-by-step process beginning with a declaration. This interpretation gained popularity during the Vietnam War and has been advanced by originalist presidential and foreign relations scholars as well as by non-originalists.⁷⁹

Other scholars, including your author, favor the Presidential View.⁸⁰ Under this approach, the Declare War Clause gives Congress the power to define the legal state of relations with another country under international law. A declaration of war, originally understood, triggered certain rights, privileges, and protections under the laws of war but was not a prerequisite for engaging in hostilities. This view relies on Article II, which vests “the executive Power” in the President and designates him as “Commander in Chief of the Army and Navy of the United States.”⁸¹ (See Essay Nos. 87, 102, and 103.) However, Congress can check the President’s powers through appropriations. The President is commander in chief, but he has nothing to command except that which Congress provides. (See Essay Nos. 59 and 60.) When Congress maintains a large standing Army and Navy, the President can engage in hostilities and Congress can use its power of the purse, oversight, impeachment, and the political process if it opposes him.

1. 3 Grotius, The Rights of War and Peace ch. III, pt. VII (A.C. Campbell trans., 1901). ↩︎
2. Id. at pt. IX. ↩︎
3. Id. at ch. IV, pt. III. ↩︎
4. E. de Vattel, The Law of Nations 399 (1797). ↩︎
5. 2 E. Vattel, The Law of Nations 23 (trans. 1759). ↩︎
6. 1 Blackstone 258. ↩︎
7. Id. ↩︎
8. 5 Cobbett’s Parliamentary History of England 234–25 (1809). ↩︎
9. John Locke, The Second Treatise of Government §§ 143–45 (J.W. Gough ed., 3d ed. 1966) (1689). ↩︎
10. Montesquieu, The Spirit of Laws bk. XI, ch. 6, ¶ 2 (David W. Carrithers ed., 1977) (1748). ↩︎
11. 1 Blackstone 257. ↩︎
12. Bernard Bailyn, The Great Republic: A History of the American People (1977). ↩︎
13. Declaration of Independence ¶ 32. ↩︎
14. Articles of Confederation, art. IX, § 1. ↩︎
15. Id., art. IX, § 6. ↩︎
16. Id., art. VI, § 5. ↩︎
17. Robert J. Delahunty & John Yoo, Making War, 93 Cornell L. Rev. 123, 134 (2007). ↩︎
18. 2 Farrand’s 137, 143. ↩︎
19. Id. at 177. ↩︎
20. Id. at 182. ↩︎
21. Id. at 318. ↩︎
22. Id. at 318. ↩︎
23. Id. ↩︎
24. Id. at 319. ↩︎
25. Id. at 505, 508. ↩︎
26. Id. at 565, 570. ↩︎
27. Id. at 590, 595. ↩︎
28. Delahunty & Yoo, supra at 127. ↩︎
29. Art. I, Sec. 10, Cl. 3. ↩︎
30. Id. ↩︎
31. Delahunty & Yoo, supra at 129. ↩︎
32. Cameron O. Kistler, The Anti-Federalists and Presidential War Powers, 121 Yale L.J. 459, 461 (2011). ↩︎
33. Storing 3.6.20. ↩︎
34. Id. ↩︎
35. 3 Elliot’s 172. ↩︎
36. Id. at 60. ↩︎
37. Delahunty & Yoo, supra at 137–38; Michael D. Ramsey, Text and History in the War Powers Debate: A Reply to Professor Yoo, 69 U. Chi. L. Rev. 1685, 1712 n.95 (2002). ↩︎
38. 3 Elliot’s 393. ↩︎
39. Letter from James Madison to Thomas Jefferson (Apr. 2, 1798), https://perma.cc/6AH7-T6GV. ↩︎
40. John C. Yoo, The Continuation of Politics by Other Means: The Original Understanding of War Powers, 84 Cal. L. Rev. 167, 177 (1996). ↩︎
41. Saikrishna Bangalore Prakash, The Separation and Overlap of War and Military Powers, 87 Tex. L. Rev. 299, 343 (2008). ↩︎
42. Alexander Hamilton, The Examination [of Jefferson’s Message to Congress] No. I (Dec. 7, 1801), https://perma.cc/A6LF-XJ7U. ↩︎
43. Alexander Hamilton, Pacificus No. I (Jun. 29, 1793), https://perma.cc/S6LT-YFN2. ↩︎
44. Yoo, The Continuation of Politics by Other Means, supra at 177. ↩︎
45. Barbara Salazar Torreon & Sofia Plagakis, Cong. Rsrch. Serv., R42738, Instances of Use of United States Armed Forces Abroad, 1798–2020, at 2 (2023), https://perma.cc/EC2U-C4QQ. ↩︎
46. Id. ↩︎
47. Yoo, The Continuation of Politics by Other Means, supra at 177. ↩︎
48. Id. ↩︎
49. Id. at 178. ↩︎
50. Id. ↩︎
51. Id. ↩︎
52. Id. ↩︎
53. Id. at 179–80. ↩︎
54. Id. at 180. ↩︎
55. 50 U.S.C. ch. 33. ↩︎
56. Yoo, The Continuation of Politics by Other Means, supra at 181–82 (quoting Letter to the Speaker of the House and the President Pro Tempore of the Senate Reporting on the Operation (Apr. 27, 1980), reprinted in Public Papers of the Presidents of the United States: Jimmy Carter 1980–81, at 777; Report of President George Bush (Dec. 21, 1989), reprinted in Thomas M. Franck & Michael J. Glennon, Foreign Relations and National Security Law 596–97 (2d. ed. 1993)). ↩︎
57. Yoo, The Continuation of Politics by Other Means, supra at 181–82, 187; John Yoo, Trump at War, 45 Vt. L. Rev. 641, 644, 660 (2021). ↩︎
58. Yoo, The Continuation of Politics by Other Means, supra at 181. ↩︎
59. Id. ↩︎
60. Id. at 181–82. ↩︎
61. Id. at 187. ↩︎
62. Yoo, Trump at War, supra at 660. ↩︎
63. Id. at 644. ↩︎
64. Id. at 648–49. ↩︎
65. Elena Moore & Roberta Rampton, Timeline: How the U.S. Came to Strike and Kill a Top Iranian General, NPR (Jan.4, 2020), https://perma.cc/SEY2-EZT9. ↩︎
66. April 2018 Airstrikes Against Syrian Chemical -Weapons Facilities, 42 Op. O.L.C. 1, 5 (2018). ↩︎
67. Id. at 22. ↩︎
68. Id. at 18 (quoting Memorandum Opinion for the Attorney General: Authority to Use Military Force in Libya, 35 Op. O.L.C. 1, 8 (Apr. 1, 2011)). ↩︎
69. John Yoo, On Unilateral Presidential War Powers, 45 Harv. J.L. & Pub. Pol’y 69, 70, 75 (2022). ↩︎
70. Zachary B. Wolf, Here’s What Biden Has Said About Sending US Troops to Ukraine, CNN (Feb. 24, 2022), https://perma.cc/5VZU-NPA8. ↩︎
71. 67 U.S. 635 (1863). ↩︎
72. Id. at 668. ↩︎
73. Orlando v. Laird, 443 F.2d 1039, 1042 (2nd. Cir. 1971). ↩︎
74. Mitchell v. Laird, 488 F.2d 611, 615 (D.C. Cir. 1973). ↩︎
75. 203 F.3d 19 (D.C. Cir. 2000). ↩︎
76. 72 Fed. Appx. 768 (10th Cir. 2003). ↩︎
77. Id. ↩︎
78. Saikrishna Prakash, Unleashing the Dogs of War: What the Constitution Means by “Declare War,” 93 Cornell L. Rev. 45, 48 (2007). ↩︎
79. Michael W. McConnell, The President Who Would Not Be King: Executive Power Under the Constitution (2020). ↩︎
80. Yoo, The Continuation of Politics by Other Means, supra at 170; H. Jefferson Powell, The President’s Authority Over Foreign Affairs: An Essay in Constitutional Interpretation 122 (2002). ↩︎
81. Robert F. Turner, The War Powers Resolution at 40: Still an Unconstitutional, Unnecessary, and Unwise Fraud that Contributed Directly to the 9/11 Attacks, 45 Case W. Rsrv. Int’l L.J. 109 (2012); John Lehman, Making War: The 200-Year-Old Battle Between the President and Congress Over How America Goes to War (1992); Robert H. Bork, Address, Erosion of the President’s Power in Foreign Affairs, 68 Wash. U. L.Q. 693, 695–701 (1990); Stephen L. Carter, The Constitutionality of the War Powers Resolution, 70 Va. L. Rev. 101 (1984); Eugene V. Rostow, “Once More Unto the Breach:” The War Powers Resolution Revisited, 21 Val. U. L. Rev. 1 (1986). ↩︎