Concept

Using Force Without a Declaration

As commander in chief

Using Force Without a Declaration

Article I gives Congress the power to declare war, and the Framers placed that power in the legislature on purpose, because English history had shown how easily a Crown could take a nation into war without Parliament's consent.¹ Read by itself, that text suggests that only Congress can start a war, and that it does so by issuing a formal declaration.² The question in this section is how far that suggestion holds when a President wants to send troops into hostilities with no declaration and no other authorization from Congress. The Commander in Chief Clause, discussed earlier in this chapter, gives the President command of forces that already exist, and it leaves open whether the same title also lets the President decide when and where those forces will fight.

Modern practice has moved a long way from the text. Over the nineteenth and twentieth centuries, Presidents sent the armed forces into hostilities on their own initiative with increasing frequency, even where no one claimed the country was defending itself against a sudden attack.³ Congress, for its part, has often authorized force through statutes that never use the word war, and it has done little to resist presidential uses of force that rest on thin claims of authority.⁴ The courts have added very little. They have dismissed most challenges to military action as nonjusticiable, which means the judiciary treats the dispute as unsuitable for decision, usually on grounds of standing, ripeness, or the political question doctrine.⁵ The Supreme Court has never clearly said when the President may use troops in hostilities without congressional approval, and because it tends to treat such foreign policy disputes as political questions, a clear answer is unlikely to come from the judiciary.⁶ The working law in this area therefore comes from text, history, and the accumulated practice of the two political branches rather than from a body of decided cases.

The three parts that follow move outward from the firmest ground. The discussion starts with the one situation in which the President's power to act first is settled, the response to a sudden attack on the United States. It then turns to deployments that go beyond defense, where the law is unsettled and practice does much of the work. It ends with the War Powers Resolution, the 1973 statute in which Congress tried to impose a framework on the President's introduction of forces into hostilities.⁷

Repelling Sudden Attacks

The President may commit the armed forces to repel a sudden attack on the United States without waiting for Congress, and this is the one use of force without prior authorization that the constitutional design plainly supports.⁸ The reason follows from the situation itself. An attack does not wait for a legislature to convene, debate, and vote, so a rule requiring prior approval would leave the country defenseless in the one circumstance where delay costs the most. At the same time, the Framers placed the declaration power in Congress so that the decision to start a war would rest with the branch that answers to the people, as the discussion above explained.⁹ The sudden-attack rule serves both aims by confining the President's unilateral power to responses: the President may protect the nation in an emergency, and the choice to begin a war stays with Congress.

The text of Article I preserves room for this response. An early draft of section 8 would have given Congress the power to "make" war, and Madison's notes on the Convention show that the verb was changed to "declare" so as to leave to the Executive the power to repel sudden attacks.¹⁰ The difference between the verbs matters because making war covers the whole business of fighting, including fighting back, while declaring war names the decision to enter a conflict. Congress keeps that decision, and a President who answers force already launched against the country has not taken it.

Lincoln's blockade of Southern ports shows the rule at work. In The Prize Cases the President proclaimed a blockade without a formal declaration of war from Congress, and the Supreme Court upheld it.¹¹ The Court agreed that Congress alone holds the power to declare a national or foreign war, but it reasoned that when a war is made against the nation, the President is "not only authorized but bound to resist force by force" and "is bound to accept the challenge without waiting for any special legislative authority."¹² The Southern states had taken up arms against the Union, so Lincoln's blockade answered a war that the other side had begun.¹³ Treat the case as background authority for the core rule. It is the only Supreme Court decision to address presidential use of troops without a congressional declaration, and it arose in the unique setting of the Civil War, so it supports the sudden-attack principle and gives little guidance beyond it.¹⁴

The line between defending and initiating is therefore the line that matters, and the usual exam error is to stretch the rule to any use of force a President chooses to call defensive. The rule is anchored in an attack on the United States. Congress's own statement of the idea in the War Powers Resolution, taken up below, lists a national emergency created by attack upon the United States, its territories or possessions, or its armed forces as one of the occasions on which the President may introduce forces into hostilities, though the constitutionality of the statute's requirements has never been definitively resolved.¹⁵ Harder questions begin where the facts leave that anchor, such as an attack on an ally or a threat to a distant interest, because the definition of defense can be stretched until it reaches foreign military action undertaken to protect other nations.¹⁶ The next subsection takes up those deployments.

Deployments Beyond Defense

The sudden-attack rule marks the one place where the President's power to act first rests on firm ground, and the law grows uncertain as soon as the facts move away from it. The text does not settle what happens next, because Congress holds the decision to declare war while the President commands the forces and conducts foreign relations. The Supreme Court has never clearly said when the President may use troops in hostilities without congressional approval, and its habit of treating foreign policy disputes as political questions makes a clear answer unlikely to come from the judiciary.¹⁸ Appeals to the Framers do not close the gap either, because a world of instantaneous communication, missiles that cross oceans in minutes, and troops that can be anywhere within hours differs sharply from the world of 1787.¹⁹ What follows is therefore mostly argument and practice rather than holdings, and each claim of presidential authority below is a position in a continuing dispute, not a rule that a court has announced.

Four situations show where the settled core ends. Each departs from the paradigm of repelling an attack already launched against the country, and each remains open:

An attack on an ally rather than on the United States raises the question whether the idea of defense can be stretched far enough to cover military action undertaken to protect other nations.²⁰
A preemptive strike, meaning force used to head off an attack that has not yet occurred, raises the question whether the President holds inherent power to wage offensive strikes when the sudden-attack rationale protects only against attacks.²¹
Reliance on a defense treaty approved by the Senate raises the question whether such a commitment supplies authority to fight, even though a treaty is made by the President with two-thirds of the senators present rather than by the whole Congress that holds the power to declare war.²²
Advance delegation by Congress, of which the Gulf of Tonkin Resolution is the standard example, raises the question how broad an authorization may be before it operates as the equivalent of a declaration, and whether even repeated funding of a war could amount to approval.²³

The four situations share one feature: in none of them is the President answering force already used against the United States, so the reason behind the sudden-attack rule, that waiting for Congress would leave the country defenseless, applies with less force or not at all. What takes its place is a comparison of degree. The closer the facts sit to defending the nation, and the more Congress has said by authorizing or opposing the action, the stronger or weaker the President's position becomes. Justice Jackson's concurrence in Youngstown Sheet & Tube Co. v. Sawyer described the case in which Congress has neither granted nor denied authority as a "zone of twilight" in which the President and Congress may have concurrent authority, or in which its distribution is uncertain, so that congressional inertia or quiescence may as a practical matter enable independent presidential action, and any actual test of power is likely to turn on events rather than on abstract theories of law.²⁴ That framework is developed later in this chapter. For now, its significance is that congressional silence is itself a fact in the analysis, which is why the same deployment can look defensible or indefensible depending on what Congress has done.

Hypothetical Illustration

Intelligence shows that a foreign government's missiles are being fueled for a launch against American territory within hours, and the President orders a strike on the launch sites before Congress can be consulted. The argument for presidential authority is at its strongest here, because the situation resembles the sudden-attack case: Congress could not meaningfully weigh in, and the strike aims at an attack that is about to happen. Change the facts. No launch is imminent, the same government has only issued threats, and Congress is in session and available to act. The President nonetheless orders an air campaign that runs for months, relying on a mutual-defense treaty with a third country that the Senate ratified, with no declaration of war and no authorizing statute. The sudden-attack rationale does not stretch to a prolonged war, and a treaty approved by the Senate is not a declaration by both houses of Congress, so the President's position is at its weakest. No court has announced either result, but the contrast shows which facts carry the argument: imminence of an attack, and whether Congress took any part in committing the nation to a long engagement.

Courts have said so little because several obstacles reinforce one another. Standing asks whether the challenger has suffered a concrete injury, ripeness asks whether the dispute has matured into a real controversy, and the political question doctrine asks whether the Constitution commits the matter to the elected branches. Challenges to military action have tended to fail one of these tests, and the vast majority have been dismissed as nonjusticiable on those grounds.²⁵ Congress adds to the silence, because it has often done little to push back against presidential uses of force that rest on thin claims of authority, and without a statute that a deployment plainly contradicts, a court has no concrete clash between the branches to decide.²⁶ The record that results contains a single Supreme Court decision on presidential use of troops without a congressional declaration: The Prize Cases, a Civil War decision upholding a blockade of Southern ports.²⁷ The usual exam error is to cite that decision for authority to deploy forces in any hostilities, when it reached only a response to a war that the Southern states had begun.²⁸

With courts largely absent, the practice of the two political branches supplies the working law. A 1967 Senate Foreign Relations Committee study concluded that the use of the armed forces against sovereign nations without congressional authorization had become common practice in the twentieth century.²⁹ The dissent in Youngstown counted at least 125 occasions on which Presidents had ordered the armed forces to act or hold positions abroad without congressional authorization or a declaration of war, among them President Roosevelt's 1941 occupation of Iceland to protect it from Axis attack after British forces withdrew.³⁰ Because that opinion was a dissent, the count is an argument rather than a holding, and the argument is examined with Youngstown later in this chapter. Practice matters in this field because each episode that Congress tolerates becomes, in the executive's telling, part of an understanding of how the war powers are divided, and that understanding in turn supports the next episode.

Modern administrations have pressed this reasoning to cover limited strikes. In April 2018 the Trump administration launched airstrikes on three Syrian government chemical weapons facilities without seeking congressional authorization.³¹ Earlier American operations against Islamic State targets had rested on the purported authority of the 2001 force authorization, but this was the first operation against a Syrian regime target, and the President instead invoked constitutional authority over foreign relations as Commander in Chief and Chief Executive, while notifying Congress within 48 hours as the War Powers Resolution requires.³² The Office of Legal Counsel later defended the strikes on two grounds: prior Presidents had deployed forces in limited engagements without prior authorization, a deeply rooted practice that reflects the established division of war powers, and the anticipated hostilities would not rise to the level of a war in the constitutional sense.³³ The second ground shows how the argument works. The declaration power attaches to war, so an administration that can characterize an operation as limited argues that Congress's power is never triggered. Critics answered that unilateral force of this kind rests on an extremely broad conception of Article II and violates international law.³⁴ The episode is a contested executive claim and not the decision of any court, and Congress's response to presidential uses of force in this period was modest: in December 2018 the Senate voted 56 to 41 to check American military assistance to Saudi Arabia's war in Yemen, but the measure died when the House declined to take up a parallel bill.³⁵

Two competing views of the constitutional division map the debate over all of these scenarios. The first treats the declaration power as a safeguard that calls for clear congressional authorization before the nation fights: no single individual should be able to take the country into war and risk everyone's lives, and a war that Congress did not unequivocally authorize at the outset is more likely to be undercut later for want of public support adequate to sustain it. Because Congress has not enforced its own role, supporters of this view want courts to rein in the executive and thereby induce Congress to discharge its responsibility.³⁶ The competing view holds that judicial involvement would be futile and harmful, since courts tend to announce hard-and-fast rules in areas of overlapping authority that are intensely political and require subtle handling. On that view the President does not act irresponsibly merely because Congress has not specifically authorized an action, so long as the President acts without legislative direction to the contrary.³⁷

The two views disagree about two things at once: who should enforce the line, and where the line sits. Courts have mostly behaved as the second view prefers, by declining to referee, which leaves the first view operating as a critique of existing practice. An answer on a deployment that falls outside the sudden-attack core should therefore present both positions and then say which facts push toward each, rather than announce a rule that no court has adopted.

Exam Analysis Steps

Because the answer here depends on how a set of facts compares with the sudden-attack core and on what Congress has done, a problem about a deployment is best organized as a sequence of questions. The steps are these:

Ask whether the facts describe a response to an attack already launched against the United States, because if they do, the sudden-attack rule supports the President without more.
Ask whether Congress has declared war or authorized the use of force by statute, including a broad advance authorization, because express or implied congressional approval places the President in the strongest position.³⁸
Ask whether Congress has restricted the deployment, because a President acting against the expressed or implied will of Congress can rely only on constitutional powers minus those that belong to Congress.³⁹
If Congress has been silent, compare the facts with defense of the nation by asking whether an attack on the United States is involved, whether the operation is a limited strike or a prolonged campaign, and what practice supports it, and then present the competing views instead of announcing a holding.

The fourth step is where most contested facts land, and the answer there is an argument rather than a holding. The first three steps resolve the easier cases, and the later sections of this chapter show how Congress has tried to turn silence into structure.

The War Powers Resolution

Where the Constitution's text and the courts both stay silent, practice fills the gap, and the practice has often been for a President to commit troops first and leave Congress to react. In 1973 Congress tried to replace that pattern with a statutory framework. Shortly after the withdrawal of troops from Vietnam, at what proved to be the high-water mark of congressional reassertion in national security affairs, it adopted the War Powers Resolution over President Nixon's veto.⁴¹ Although it carries the name of a resolution, it is a federal statute, passed through the full legislative process and still in force.⁴² The immediate cause was Vietnam, a highly unpopular war that two Presidents, Lyndon Johnson and Richard Nixon, fought at great cost in lives and money without a formal declaration of war from Congress.⁴³

The problem the statute addresses is one of timing and leverage. A President who sends troops into a conflict first leaves Congress with a choice made after the fact: fund the intervention or cut off an army already in the field, and cutting off the army is a politically suicidal act.⁴⁴ Because refusing money looks like abandoning soldiers, the President's first move would in practice settle the question, whatever the declaration power says on paper. The Resolution responds by moving the decision point forward and changing what congressional silence means. Without a clock, inaction leaves the forces in place; with the clock described below, inaction eventually requires them to come home, so the burden of obtaining approval falls on the President rather than on a Congress that would otherwise have to defund the troops. The statute states its aim directly: to ensure that the collective judgment of Congress and the President governs both the introduction of forces into hostilities, or into situations where hostilities are clearly imminent, and the continued use of those forces.⁴⁵

The framework works through three mechanisms that operate in sequence, and each is best learned with its trigger and its consequence:

The first is a reporting duty: in the absence of a declaration of war, when the President introduces armed forces into hostilities, into situations where imminent involvement in hostilities is clearly indicated, or into the territory, airspace, or waters of a foreign nation, the President must report to Congress, typically within 48 hours.⁴⁶
The second is a sixty-day clock: after giving notice, the President generally has 60 days to obtain a declaration of war, a statutory authorization, or an extension of the period, and must withdraw the forces if none arrives.⁴⁷
The third is a removal power: Congress may at any time order the withdrawal of the forces by concurrent resolution, which is a resolution not subject to a presidential veto.⁴⁸

Beyond those three, the statute also directs the President to consult with Congress in every possible instance before introducing forces into hostilities, and to consult regularly afterward until the forces are no longer engaged.⁴⁹

Read together, these provisions countenance a temporary period of unilateral presidential engagement, and two restraints bound that period: Congress alone can order a stand-down at any time, and any continuation past the sixty days needs affirmative legislative approval.⁵⁰ The statute also records Congress's view of the underlying constitutional question. It says the President's powers as commander in chief to introduce forces into hostilities, or into situations where hostilities are clearly imminent, are exercised only pursuant to a declaration of war, specific statutory authorization, or a national emergency created by an attack upon the United States, its territories or possessions, or its armed forces.⁵¹ The third condition tracks the sudden-attack rule taught earlier in this chapter, so the statute recognizes the one use of force the constitutional design plainly supports and asks for something more from Congress in every other case. The second condition carries a detail worth holding onto, because the phrase specific statutory authorization excludes mere congressional appropriations.⁵² That exclusion answers, at least on the statute's own terms, the earlier question whether repeated funding of a war could amount to approval, and it protects the statute's purpose: if funding counted as authorization, Congress's payment for troops it could not realistically cut off would supply the approval, and the dilemma the statute was built to avoid would return.

Hypothetical Illustration

Forces of a foreign government sink a United States warship and shell a nearby naval base, and the President orders the military to respond at once. The statute's own statement of presidential authority lists a national emergency created by an attack on the United States or its armed forces as a basis for introducing forces, so no declaration or specific authorization is needed to justify the response, although the reporting duty still applies in the absence of a declaration of war. Change the facts: no attack has occurred, the foreign government has only made threats, and the President sends troops into a prolonged engagement with no declaration and no authorizing statute. None of the three conditions is met, and the President is relying on constitutional authority alone, which the statute's text does not list as a basis.

Whether Congress may bind the President in this way is the contested question. President Nixon's veto message rested heavily on constitutional objections: the bill, he said, "would attempt to take away, by a mere legislative act, authorities which the President has properly exercised under the Constitution for almost 200 years," and he was particularly troubled that certain commander-in-chief powers would end automatically without overt congressional action.⁵³ The objection has a structural logic, since the Commander in Chief Clause gives the President command of the forces, and a statute that ends a deployment by the passage of time operates on that command without any vote by Congress at the moment of termination. Supporters answer from Article I: Congress holds the power to declare war, and the Necessary and Proper Clause reaches powers vested in any department or officer of the government, so the statute rests on a recognized source of legislative power.⁵⁴ One defense reads the Resolution as a congressional definition of the word war in Article I that intrudes on no presidential prerogative. Criticism also comes from the other direction: the statute is unnecessary because the appropriations power already gives Congress ample control, or it is objectionable because one Congress cannot bind later Congresses to a particular form of approval.⁵⁵

Presidents have answered the dispute with a consistent position. They have insisted that the Resolution is not constitutionally binding on them, and whether they comply with its terms has depended more on their political standing than on legal obligation.⁵⁶ The 2018 airstrikes on Syrian government chemical weapons facilities show how that stance works. The Trump administration notified Congress within 48 hours, as the Resolution requires, and in the same letter grounded the strikes in the President's constitutional authority over foreign relations as Commander in Chief and Chief Executive, so no declaration or specific statute was claimed.⁵⁷ The reporting duty was met in form while the premise that congressional approval was needed went unconceded. A report costs little and need not concede the statute's premise, which makes it the easiest of the mechanisms to honor.

A court test of these competing positions is unlikely. There is no definitive resolution of the constitutionality of the Resolution's requirements or of their effectiveness.⁵⁸ A challenger would first have to show standing, and the dispute would then have to survive the ripeness and political question doctrines that have led courts to dismiss the vast majority of challenges to military action as nonjusticiable.⁵⁹ Who could even bring the issue, and whether it is justiciable at all, remain open questions, so the Resolution's legal force has stayed largely theoretical.⁶⁰

If a President did defy the Resolution and a court reached the merits, the dispute would fall at the low end of Justice Jackson's framework from Youngstown, which is developed later in this chapter. The President would be invoking executive powers in the face of an explicit limit imposed by Congress, which is Jackson's third category, where presidential power is at its lowest ebb because the President can rely only on constitutional powers of the office minus any constitutional powers of Congress over the matter.⁶¹ A court could sustain the President in that posture only by disabling Congress from acting on the subject.⁶² That framing shows what the President would have to establish, namely that the introduction and continuation of forces in hostilities lies so completely within the commander's authority that Congress cannot regulate it at all. The placement assumes the Resolution is a valid exercise of congressional power, which is the very point in dispute, so it describes how the argument would be structured and says nothing about how any court has resolved it.

Key Exam Rule

War Powers Resolution

Enacted in 1973 over President Nixon's veto, the War Powers Resolution requires the President, absent a declaration of war, to report to Congress typically within 48 hours of introducing forces into hostilities, requires withdrawal after 60 days unless Congress declares war, authorizes the action, or extends the period, and lets Congress order removal at any time by concurrent resolution. It also states that the President's commander-in-chief power to introduce forces is exercised only under a declaration of war, specific statutory authorization, or a national emergency created by an attack on the United States or its forces. Presidents have uniformly denied that it binds them, its constitutionality has never been definitively resolved, and standing and justiciability obstacles make a court test unlikely, so a President who defied it would fall into Jackson's third category, where presidential power is at its lowest ebb.⁶³