The Underappreciated Legacy of the War Powers Resolution

Fifty years ago this week, Congress took a novel and unprecedented step toward reclaiming a more central role in matters of war and peace. Over a veto by President Richard Nixon, a bipartisan supermajority in both chambers enacted what they dubbed the War Powers Resolution, a law whose stated purpose was to “fulfill the intent of the framers” by ensuring that “the collective judgment of both the Congress and the President will apply to the introduction of [U.S.] Armed Forces into hostilities” moving forward.

Few pieces of legislation, however, have fallen so far short of their stated aspirations so quickly. Just two years after the War Powers Resolution’s enactment, several of its sponsors convened a series of hearings to examine how “the executive branch proclivity … toward evasive and selective interpretation” had undermined compliance with its requirements. Within a decade, the executive branch’s continued unilateral use of the military had even architects of the War Powers Resolution declaring it a failure. When then-Sen. Joe Biden chaired a special Senate subcommittee examining the War Powers Resolution’s effectiveness on the occasion of its 15th anniversary, he ultimately concluded that whole new legislation was needed. Most other assessments in the ensuing 35 years have similarly maintained that the War Powers Resolution is “useless” and “doomed to fail[,]” in large part because defects in its design—and an executive branch willing to capitalize on them—has rendered it ineffective.

There is undoubtedly much truth in these criticisms. Yet they too often obscure another, equally true observation: that, for all its flaws, the War Powers Resolution has still proved to be a revolutionary piece of legislation. While it has not achieved its own vision of “collective judgment” on matters of war and peace, the War Powers Resolution has both constrained the executive branch and empowered Congress in substantial and often underappreciated ways. Perhaps more importantly, it has also helped to vindicate Congress’s constitutional role in such matters. As we continue to wrestle with the separation of powers around matters of war and peace half a century into its existence, it is worth acknowledging these aspects of the War Powers Resolution’s legacy—not least because they may yet bear on where that broader debate may lead.

Constraining the Executive Branch

The primary function of the War Powers Resolution was always to impose some constraints on the president’s ability to deploy U.S. military personnel into armed conflicts on his own authority. Congress had just spent several years watching the Nixon administration interpret around statutory limits and rely on an admixture of inherent presidential authority and implicit congressional authorization to continue military operations in and around Vietnam, over increasingly strident congressional objections. The War Powers Resolution was intended to help make sure that did not happen again by setting limits on what the president can do without Congress.

The provision of the War Powers Resolution that looks the most like a limitation on the president’s authority is undoubtedly Section 2(c), which describes the president’s constitutional authority to enter U.S. troops into hostilities absent statutory authorization as being limited to situations where there is “a national emergency created by attack upon the United States, its territories or possessions, or its armed forces”—a far narrower view of presidential authority than many maintain, including most in the executive branch. But looks can be deceiving. Later, Section 8(d)(1) of the War Powers Resolution disavows any intent to alter the constitutional authority of the president, suggesting that Section 2(c) is—as relevant legislative history and the title of Section 2, “purpose and policy,” seem to confirm—simply a statement of Congress’s views that is not intended to have any legal effect. Or at least, this is how the executive branch quickly interpreted it shortly after the War Powers Resolution’s enactment, without raising major objections from Congress. As a result, this narrow vision of the president’s authority has never operated as a substantive limitation.

Instead, the main constraint that the War Powers Resolution puts on the president is a procedural one layed out several provisions later. Section 4(a)(1) of the War Powers Resolution requires that the executive branch notify Congress within 48 hours of U.S. armed forces being “introduced … into hostilities or into situations where imminent involvement in hostilities is clearly indicated by the circumstances” absent statutory authorization. Section 5 in turn directs that, unless Congress provides specific authorization, extends the period by statute, or is “unable to meet as a result of an armed attack upon the United States[,]” the president “shall terminate” any such use of the military within 60 days—a period that the president can extend by an additional 30 days by certifying to Congress that doing so is necessary to remove those armed forces safely. In other words, whatever independent constitutional authority a president might have to deploy the military into hostilities, he or she may do so for only 60 to 90 days before seeking approval by Congress unless otherwise expressly authorized. Continuing past this deadline means that the president is acting in contravention of an express statutory directive, circumstances in which the president’s constitutional authority is generally considered to be at its “lowest ebb[.]”

This sort of 60- to 90-day time limit does not prevent the executive branch from using the military in a variety of more limited situations, for whatever purposes the executive branch believes are constitutionally valid. But it is insurance against the type of conflict that was most front of mind for the War Powers Resolution’s authors: an extended, unauthorized war of the sort that had recently taken place in Vietnam.

That said, even this limited statutory framework has a significant weakness: Its application hinges on statutory language—“introduced … into hostilities”—that the War Powers Resolution fails to define. Legislative history shows that members of Congress substituted “hostilities” for “armed conflict” when drafting the War Powers Resolution to cover a broader range of circumstances, including those presenting “a clear and present danger of armed conflict.” But they were unable to reach agreement on a more concrete definition, leaving the language open for the executive branch to interpret and apply, in line with the president’s constitutional responsibility to “take Care that the Laws be faithfully executed.”

For this reason, in 1975, relevant committees in Congress asked the Ford administration how it had understood and applied these terms in relation to the first several war powers reports it had filed. Senior officials responded that, while each case was fact specific, the executive branch generally understood “hostilities” as being limited to “a situation in which units of the U.S. armed forces are actively engaged in exchanges of fire with opposing units of hostile forces” and “imminent hostilities” to mean “a situation in which there is a serious risk from hostile fire to the safety of [U.S.] forces.” Subsequent executive branch legal opinions narrowed this understanding further, including by excluding from its scope “sporadic military or paramilitary attacks on [U.S.] armed forces stationed abroad” and situations where U.S. personnel stationed overseas are “fired upon and defen[d] themselves[.]”

The executive branch’s ability to interpret “hostilities” and related statutory language in these ways has undoubtedly allowed it to evade the 60- to 90-day limit in any number of cases where it might reasonably have applied. The clearest example came in 2011 when the Obama administration chose to interpret “hostilities” as not extending to situations where U.S. forces “engage in a military mission that involves limited exposure for U.S. troops and limited risk of serious escalation and employs limited military means”—an interpretation that allowed it to continue airstrikes in Libya past the 60- to 90-day limit. Prior administrations had similarly framed related military operations as separate incidents to restart the clock and thereby avoid the 60- to 90-day time limit. More recently, the Trump administration angered members of Congress by asserting that the definition of “hostilities” did not reach the various types of U.S. assistance being provided to the Saudi-led military campaign in Yemen.

Yet the controversy surrounding these permissive interpretations has too often distracted observers from a more fundamental observation: that outside of these contested cases, the War Powers Resolution’s 60- to 90-day clock actually has an impressive record of compliance.

The executive branch has never argued that Congress lacks the authority to require the sorts of reports required by Section 4(a)(1). While there are a number of cases where the executive branch hasn’t provided these reports—or has obfuscated whether a report is being provided pursuant to Section 4(a)(1) or another reporting obligation not tied to the 60- to 90-day clock—nearly all fall within the scope of one of the permissive interpretations that the executive branch has advanced. And perhaps more importantly, as liberally as the executive branch has read terms like “hostilities,” it has never been so brazen as to interpret them to exclude those activities most indisputably in mind by those who drafted the War Powers Resolution: namely, the extended deployment of ground troops into situations of sustained and active danger. 

As a result, the executive branch has never indisputably pushed these sorts of military operations clearly past the 60- to 90-day limit. The most straightforward data point in this regard is that, in the past half-century, the United States has not entered into a major armed conflict without statutory authorization from Congress, as it once did in Korea and during the later stages of the Vietnam War. While some presidents have asserted the legal authority to do so, none has actually relied on that theory. Instead, all three major armed conflicts that the United States has initiated in the past half-century—the 1991 Gulf War, the 2001 invasion and subsequent occupation of Afghanistan (and ensuing global counterterrorism operations), and the 2003 invasion and occupation of Iraq—were ultimately authorized by Congress. 

Nor has the executive branch pursued more limited active military operations that unabashedly extend past the 60- to 90-day time limit. Even the more ambitious military operations that some presidents have pursued on their own authority—such as the 1983 invasion of Grenada and 1988 invasion of Panama, both of which were efforts at regime change—were conspicuously completed within the 60- to 90-day time limit. Other more extended military operations, such as the Obama administration’s 2014 military campaign against the Islamic State in Iraq and the Levant, were ultimately pursued under broad readings of existing statutory authorizations—a practice that may be problematic in its own right but nonetheless technically complies with the War Powers Resolution’s restrictions.

To be certain, the scope of this constraint is undoubtedly narrower than the authors of the War Powers Resolution expected. But even if it only reaches the use of ground troops in extended armed conflicts, this is no small feat, especially coming so soon after experiences in Korea and Vietnam.

Empowering Congress 

Another closely related objective of the War Powers Resolution was to strengthen Congress’s own role in wartime decision-making. The authors of the War Powers Resolution were not simply trying to restrain the president’s ability to engage in foreign wars. They also wanted Congress to have more of a voice in determining when and how the United States chooses to go to war. Recent experience suggests that the War Powers Resolution has helped to do exactly that—only not in the way its authors expected. 

Section 3 lays out what many observers view as the main provision within the War Powers Resolution aimed at empowering Congress: a directive that “[t]he President in every possible instance shall consult with Congress before introducing [U.S.] Armed Forces into hostilities[.]” Yet this requirement, like the definition of hostilities, was left quite open ended. Legislative history suggests that the use of “every … instance” was supposed to establish an expectation that such interbranch consultation would be the norm, while “possible” was intended to acknowledge that there may be cases where exigent circumstances warrant consultation impracticable and thus unnecessary. “Consult,” meanwhile, was described as going beyond simple notice to an actual exchange of views. But in the end, Congress chose to omit any specific statutory guidance on how Section 3 should be read, leaving the precise details to be filled in by Congress and the executive branch through subsequent practice.

Such practice has in turn been a bit all over the map. The Ford administration established a baseline understanding of Section 3 by informing congressional leaders of certain intended military actions in relation to Vietnam and Cambodia shortly after the War Powers Resolution was enacted, but without seeking feedback or input. The Carter administration, meanwhile, withheld notice of its attempted rescue of Iran hostages in 1980 on the grounds that the need for secrecy made consultation impossible. Subsequent presidential administrations have generally embraced one of these two approaches depending on the circumstances, with occasional divergences into more substantive ex ante discussion. Most of these exchanges undoubtedly fall short of the sort of “collective judgment” promised by the War Powers Resolution’s own stated purpose and they have been a point of contention with Congress almost since shortly after the War Powers Resolution’s enactment. But the open-endedness of Section 3’s actual statutory language makes it hard to say with certainty that these efforts are necessarily inconsistent with the War Powers Resolution. 

Instead, in the absence of substantive consultation, another set of provisions in the War Powers Resolution have come to play a greater role in empowering Congress: those establishing “priority procedures,” meaning special legislative procedures for enacting certain types of legislation on an expedited basis. Adjusting internal rules that are nominally within Congress’s control may seem like a strange form of empowerment. But by helping Congress to act with more agility than its regular procedures generally allow, these provisions have enhanced Congress’s ability to speak out as an institution on related issues.

As originally written, the War Powers Resolution established two parallel sets of priority procedures, each of which was designed to ensure that Congress meaningfully engaged with and voted on certain types of war-related measures if introduced. Specifically, the procedures were meant to guarantee that Congress debated and voted on qualifying measures in a fixed period of time, and actually enacted those measures if the majority of both chambers supported it. Section 6 does so for joint resolutions and bills that provide specific statutory authorization for deployments of armed forces into hostilities. Section 7 does the same for concurrent resolutions directing the president to remove military personnel from such circumstances, a measure that Section 5(c) in turn required the president to comply with. This sort of measure was known as a “legislative veto,” as concurrent resolutions, unlike joint resolutions and other conventional legislation, need not be presented to the president for a signature or veto in order to be enacted, allowing a majority of both chambers to effectively overrule executive branch action. That said, the Supreme Court’s 1983 decision in INS v. Chadha complicated this arrangement,  as it called the constitutionality of this sort of legislative veto into serious question, on the grounds that it evaded the Constitution’s requirement that legislation be presented to the president for signature or a possible veto. In response, Congress enacted a third set of updated expedited procedures (later codified at 50 U.S.C. § 1546a) for joint resolutions and bills that similarly require the removal of U.S. armed forces from hostilities, though they served to expedite such measures only in the Senate, not the House.

For the first several decades of the War Powers Resolution’s existence, these procedures were employed only occasionally and rarely to much effect. But in 2017, members of Congress began making novel use of them to raise concerns about the Trump administration’s foreign policy, first in relation to its support of the Saudi-led military campaign in Yemen and later in relation to its targeted killing of Iranian military commander Qassem Soleimani. Early efforts used concurrent and joint resolutions to compel floor debates on these policies. They also forced related procedural votes, which were often perceived as a proxy referendum on Trump’s policies. But as congressional opposition to Trump’s use of the military became more significant, these efforts increasingly became focused on enacting joint resolutions that might actually require the Trump administration to change its behavior. In the end, while bipartisan majorities in both chambers enacted joint resolutions attempting to push back on Trump’s actions in both the Yemen and Iran contexts. Trump ultimately vetoed them, however, and neither measure received the two-thirds support in both chambers necessary to override.

Even if enacted, the legal effects of these resolutions would have been open to some question. What is not in question, however, is their political impact, as each debate and resulting vote served as high-profile demonstrations of bipartisan concerns with the Trump administration’s policy decisions within Congress—views that garnered more and more public salience as the debates wore on. In essence, these measures lowered the threshold for congressional action from the usual supermajority that congressional procedures require to something closer to the constitutionally required simple bicameral majority. This in turn allowed Congress as a whole to weigh in on an ongoing debate over matters of war and peace in ways that would otherwise have been impossible. In this sense, the War Powers Resolution unchained Congress on certain matters of war and peace, if not in the ways that its authors might have anticipated. 

Confirming Congress’s Authority

The most significant legacy of the War Powers Resolution, however, may be a constitutional one. This will no doubt sound strange to observers who are familiar with the oft-repeated (and technically correct, if somewhat misleading) refrain that “every President has taken the position that [the War Powers Resolution] is an unconstitutional infringement by Congress on the President’s authority as Commander in Chief.” But the constitutional debate around the War Powers Resolution is more nuanced than this account allows and does more to vindicate Congress’s authority than most observers acknowledge.

Contrary to popular belief, the executive branch has never argued that the War Powers Resolution as a whole is unconstitutional. Instead, at various points, the executive has argued that certain provisions of the War Powers Resolution are unconstitutional or may be unconstitutional when applied in certain circumstances. For many years, the most notable of these arguments was that Section 5(c)’s use of a concurrent resolution as the trigger for the president’s obligation to remove U.S. armed forces from hostilities constituted an unconstitutional legislative veto—a view that the Supreme Court more or less vindicated in INS v. Chadha. Elsewhere, the executive branch has similarly argued that provisions purporting to limit the executive’s ability to read implicit authorization into appropriations statutes and other measures impose unconstitutional constraints on future congresses. As a result, the executive branch has generally treated these provisions as creating rebuttable presumptions as opposed to hard prohibitions. In this sense, it is correct that every presidential administration questioned the constitutionality of at least part of the War Powers Resolution. But this does not mean that they did not accept other provisions as valid and binding. 

The most important constitutional debate, however, has centered on what is arguably the heart of the War Powers Resolution: the 60- to 90-day time limit. In his veto statement, President Nixon argued that this provision—along with the legislative veto in Section 5(c)—was “clearly unconstitutional,” on the grounds that it “would attempt to take away, by a mere legislative act, authorities which the President has property exercised under the Constitution for almost 200 years.” But the executive branch’s views have shifted over time, in a direction that may do more to vindicate Congress’s authority over such matters than reject it.

To understand how this could be the case, one must go back to the early days of the Cold War. In 1950, the Truman administration chose to justify its intervention in Korea on the basis of a dramatic claim of presidential authority instead of seeking authorization from Congress. In a related memorandum justifying this decision, Secretary of State Dean Acheson—himself a prominent constitutional lawyer—used a history of smaller scale, presidentially initiated military engagements that dated back to the 18th century to argue that, in making the president the “Commander in Chief[,]” the Constitution gave the president plenary authority over the use of military force. Acheson’s original memorandum defending this position did not even acknowledge that the Constitution gave Congress, not the president, the authority “[t]o declare War[.]” Subsequent administration statements in turn made clear that they did not believe that this cabined the president’s own authority in any meaningful way. Indeed, in related congressional testimony, Acheson even went so far as to suggest that the authority to direct military operations was exclusive to the presidency and thus could not be made subject to statutory limitations, though he conceded that Congress could withhold appropriations for the military as a whole.

Subsequent presidential administrations were often not as bullish on this broad vision of presidential authority, at least in their internal legal discussions. But few were inclined to openly repudiate it, in part because maintaining the availability of that argument preserved flexibility and gave the president more credibility in threatening the use of force—something the executive branch viewed widely as an important tool for deterrence. As a result, the view that Congress had no authority to set limits on the president’s authority to use military force was very much a live one headed into the 1970s.

Of course, not all members of the Nixon administration shared this view. As early as 1970, then-Assistant Attorney General (and later Chief Justice) William Rehnquist had provided the Nixon White House with an internal legal memorandum expressing the view that “Congress undoubtedly has the power in certain situations to restrict the President’s power as Commander in Chief to a narrower scope than it would have had in the absence of legislation.” In Rehnquist’s view, this did not mean “that every conceivable condition or restriction … would be free of constitutional doubt[.]” But it did suggest that Congress could likely impose some limits on the use of force by statute if it saw fit to do so.

While Nixon’s veto statement adopted a contrary view, Rehnquist’s perspective reemerged after the War Powers Resolution was enacted. The Ford administration declined to take a position on the constitutionality of the 60- to 90-day clock. But the Carter administration issued a 1980 legal opinion confirming its view that “Congress may, as a general constitutional matter,” impose such a statutory limit, in part because the 60- to 90-day time frame was “sufficient under any scenarios we can hypothesize to preserve [the president’s] constitutional function as Commander-in-Chief.” A later 1984 legal opinion issued by the Justice Department during the Reagan administration declined to go quite so far but did not identify the 60- to 90-day time limit as unconstitutional, as it did with other parts of the War Powers Resolution.

That said, both the Reagan and George H.W. Bush administrations were openly critical of the War Powers Resolution and sought its repeal. As part of this effort, they questioned its constitutionality, going so far as to issue signing statements preserving “the longstanding positions of the executive branch on … the constitutionality of the War Powers Resolution” when seeking congressional authorization for the use of military force, without clarifying exactly what that position was. The closest either administration got was 1988 testimony by State Department legal adviser Abraham Sofaer, in which he asserted that the 60- to 90-day time limit was unconstitutional on the grounds that the president “has the constitutional authority and responsibility … to deploy and use U.S. forces in a variety of circumstances, such as in the exercise of our inherent right of self-defense[.]” He also implied that the passive expiration of a time limit raises similar constitutional questions as a legislative veto. Both critiques, however, are closer to Rehnquist’s views than Nixon’s or Truman’s outright rejection of Congress’s constitutional authority. 

A subsequent internal 1993 legal assessment by career Justice Department attorneys expressly rejected Sofaer’s assessment of the constitutionality of the 60- to 90-day time limit. Instead, along lines similar to Rehnquist, it concluded that “in most circumstances the [60- to 90-day time limit] would not unconstitutionally restrict the President’s ability to exercise his inherent authority regarding the use of force” while acknowledging that there may well be certain exigent circumstances where it could, including those related to U.S. self-defense.

The Clinton administration largely declined to take a position on the matter in its own formal legal opinions. The George W. Bush administration, meanwhile, returned to the hostile posture toward the War Powers Resolution of prior Republican administrations. But the legal opinions it issued in its early years supporting an exceptionally broad vision of presidential authority over the use of military force were careful in their critique of the 60- to 90-day limit’s constitutionality. A 2001 legal opinion asserting that the president has broad constitutional authority to pursue counterterrorism operations in the wake of the Sept. 11, 2001, attacks maintained that Congress could not regulate the president’s use of “emergency authority” relating to national self-defense—an exception of the sort anticipated by Rehnquist, albeit broad in scope. A later 2002 legal opinion supporting the president’s inherent constitutional authority to invade and occupy Iraq acknowledged prior constitutional critiques of the 60- to 90-day limitation but declined to take a firm position; instead, it conceded that “[i]f the President were to take military action without complying with the [War Powers Resolution] [then] litigation would [likely] be brought,” but ultimately relied on the fact that “it is unlikely … a court would rule on the merits” due to justiciability barriers and the federal courts’ traditional reluctance to weigh in on such matters. In both cases, President Bush ultimately opted to pursue congressional authorization, though he issued signing statements reserving possible constitutional objections to the War Powers Resolution. In the waning days of the administration, the Justice Department also issued a memorandum rescinding or caveating many of its post-Sept. 11 opinions in order to acknowledge that “the Constitution also grants significant war powers to Congress”—a shift in perspective that would no doubt have implications for the War Powers Resolution, though neither the 2001 nor 2002 legal opinions mentioned above was formally rescinded.

For its part, the Obama administration largely continued this latter perspective. Even as it pushed for a narrower reading of “hostilities,” it openly “recognize[d] that Congress has powers to regulate and terminate uses of force.” Notably, it also included War Powers Resolution limitations in the legal and policy framework it articulated governing the use of military force, without either acknowledging or denying the existence of possible constitutional exceptions. Neither the Trump nor Biden administration, meanwhile, has publicly wrestled with this question at any length, most likely because they have not pursued uses of military force that they view as implicating it. But nor have they noted any departures from the Obama administration’s stated views, despite statutory obligations that they do so.

To be certain, this evolution of executive branch views is no clean-cut vindication of the 60- to 90-day time limit’s constitutionality. But it’s also far from an outright repudiation. To the contrary, the most consistent thread—dating back to before the War Powers Resolution and persisting, albeit subtly, through the legal assessments of even those administrations most actively hostile to the 60- to 90-day time limit—is that statutory limits on the use of military force have to be taken seriously. Perhaps there are circumstances in which the president has the exclusive constitutional authority to act in spite of statutory restrictions, and different presidential administrations have expressed different views on the breadth of these exceptions and how likely they are to conflict with the 60- to 90-day clock. But implicit in this analysis is an acknowledgment that Congress can otherwise legislate restrictions on the use of military force—and that those restrictions generally have to be respected by the executive. Indeed, this may be why those administrations most opposed to the War Powers Resolution on policy grounds were so intent on rescinding it—and why they generally complied with its requirements, even as it threw their constitutionality into question.

To many observers, such a concession may seem like a precious small victory. But it is an important one, in that it rejects wholesale the truncated view of congressional authority put forward by the Truman administration. Instead, to push back on Congress’s authority to regulate the use of military force by statute, the executive branch must make claim that the Constitution has exclusively vested the president with the authority to take the action in question—a bold claim that the Supreme Court has made clear should be “scrutinized with caution,” putting the president on disadvantageous terrain. This doesn’t mean that the executive branch will never assert the constitutional authority to disregard the 60- to 90-day time limit (or some other statutory limitation Congress chooses to impose). But particularly when one considers this possibility against the record of compliance with the 60- to 90-day limit over the past half-century, it does not seem to be a step the executive branch is likely to take lightly—leaving Congress with a great deal of influence it can wield, if it chooses to do so. 

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The scholar Edwin Corwin once famously described the Constitution’s assignment of authority over foreign affairs as “an invitation to struggle,” and the debate over the constitutional assignment of war powers is no exception. Enacting the War Powers Resolution was a major salvo on the part of Congress in this broader engagement. But it should not necessarily be surprising that the executive branch has persistently pushed back on the broader visions of how that law would work, particularly as the authors of the War Powers Resolution provided ample opportunity for them to do so. 

The legal framework that has emerged from this struggle is certain to be a disappointment for those who want to see Congress adopt the central role in wartime decision-making that the War Powers Resolution seemed to promise. But that does not render it a complete failure. Five decades of experience show not only that the War Powers Resolution has helped to restrain the executive branch and empower Congress in meaningful ways but also that it has served to vindicate the once-maligned idea that Congress has a constitutional role to play in such matters. In this sense, it has served as an important (if imperfect) corrective to the overreaches of executive authority to which it was responding and has helped provide a foundation for a more closely shared authority over matters of war and peace moving forward, if and when Congress chooses to assert such a role for itself.