This week brought a vivid illustration of why it is so important to reinvigorate congressional war powers as a buffer against slipping into imprudent conflict.

On Sunday, the United States struck three targets linked to Iran-backed paramilitary forces in Iraq and Syria, killing four fighters, and destroying facilities that it said were, among other things, used for drone attacks on U.S. troops. It claimed that it was acting to defend U.S. troops, including by deterring and disrupting future attacks. The groups quickly struck back (with no fatalities) and pledged an “open war” with the United States.

The justification that U.S. officials offered publicly and privately was straightforward: The United States needs to protect its troops, who are increasingly harassed, particularly by new, more precise drones. Under an approach to domestic and international law that has been fairly consistent over the past few administrations, strikes of the sort the Biden administration took earlier this week are lawful: the 2001 Authorization for Use of Military Force authorizes U.S. troops to wage a counter-ISIS campaign in Iraq and Syria, while the right of self-defense allows the U.S. president to protect them against armed attacks under the U.S. constitution and UN Charter.  The choice of targets along the Iraq-Syria border was calibrated to send a signal without escalating tensions.

But critics in the U.S. Congress and elsewhere expressed skepticism. They noted that this was the administration’s second set of strikes against Iran-backed groups in the region (the first was in February), asked whether this suggested that deterrence was an unachievable objective, and queried whether the administration ought to be exchanging fire like this absent congressional authorization. Some wondered why, in light of ISIS’ degradation, U.S. troops still need to be in Iraq at all.

These are all fair questions, but it is not clear whether or how they will be answered. As has become executive branch practice, the administration put out carefully parsed information intended to make clear that the strikes met relevant legal criteria but offered little to inform public debate about the underlying policy issues. This approach evoked the warning Professor Rebecca Ingber published after the February strikes, when she wrote that an exaggerated focus on pliant legal justifications could facilitate the United States’ slide into fresh conflict in the Middle East without sufficient examination of the stakes.

The risk of escalation could be increased if a  reported (but not officially confirmed) policy change by the Biden administration regarding how the U.S. responds to attacks on U.S. forces and facilities is implemented. According to the Washington Post, during the Trump administration, the U.S. would respond with force only to those attacks which killed Americans.  But an unnamed source told the Post that under the new policy, the United States will respond with force to any attack, regardless of whether that attack caused casualties or fatalities. While the aim of any such policy might be deterrence, some groups may see advantages in provoking increased U.S. activity, which could undercut support for the U.S. presence in Iraq.

Neither the Biden administration, nor Congress, seems to want a war with Iran-backed proxies, much less Iran itself. But as this week’s news demonstrates, because so much power has accreted in the executive branch when it comes to matters of war and peace, the risk of stumbling into one for insufficiently examined reasons is too high. Congress is in a position to help manage this risk. But to do so it will need to revive its atrophying war powers.

Flaws in the Framework

The risk of drifting into an imprudent war against Iran or its proxies flows from several related flaws in the United States’ war powers framework.

First, Congress has through inaction and acquiescence allowed outdated use of force authorizations such as the 2001 and 2002 Authorizations for Use of Military Force (AUMFs) to remain on the books for decades, and left the executive branch largely to its own devices in interpreting them. Successive administrations have taken advantage of this latitude to read these statutes as conferring authority to wage conflicts that could scarcely have been imagined when they came into force. Most relevant here is that three successive administrations, starting with President Obama’s, have cited the 2001 AUMF as the statutory authority for the military campaign against ISIS – an organization that did not exist when the law was enacted. The counter-ISIS mission is the stated reason for U.S. combat forces to be in Iraq and Syria.  (As noted above, although the stated domestic law basis for the recent strikes was solely Article II of the Constitution, the underlying mission in Iraq and Syria relies on the 2001 AUMF.)

Second, the executive branch has over time taken an increasingly capacious view of the President’s authority to direct the use of force under the Commander-in-Chief clause of Article II of the Constitution. Under theories advanced by the Department of Justice’s Office of Legal Counsel (OLC), the President has unilateral authority to use force to advance a broad set of “national interests” so long as it is not anticipated to result in “war in the constitutional sense” (i.e., a conflict that OLC regards as sufficiently major to require congressional approval).

Although the defense of U.S. forces and citizens is widely accepted as such an interest, the President’s discretion to determine what this entails is itself expansively understood by executive branch lawyers. The classical understanding of the president’s self-defense powers was linked to repelling “sudden attacks,” but that understanding has broadened over time. In the present case, while it is possible that the United States had concrete evidence that it could thwart an imminent attack by targeting the facilities it struck or otherwise mitigate the threat to the U.S. forces through these actions, it has not shared this publicly. Rather, in the war powers report filed on June 29, President Biden explained in general terms that he ordered the strikes to “protect and defend the safety of our personnel, to degrade and disrupt the ongoing series of attacks against the United States and our partners, and to deter the Islamic Republic of Iran and Iran-backed militia groups from conducting or supporting further attacks on United States personnel and facilities.”

Third, after years of ceding power through open-ended statutory grants and acquiescence in executive branch overreach, Congress currently has relatively few tools to constrain the president’s use of force. Five decades ago, it was in a better place. As the Vietnam War drew to a close, Congress enacted the 1973 War Powers Resolution (WPR) in an effort to prevent future administrations from surreptitiously starting or expanding conflicts without congressional approval. Among other things, the WPR permitted the two houses of Congress to force a withdrawal of troops from hostilities through a concurrent resolution – i.e., a resolution enacted by a majority of each chamber without the president’s signature.

But the Supreme Court upended these efforts. In INS v hadha (1983) the Court ruled unconstitutional the so-called legislative veto in a decision that is generally understood to mean that acts of Congress must have the president’s signature to enjoy the force of law. Now, as a result, Congress must be able to summon the supermajority required to overcome a veto if it wishes to terminate hostilities in the face of presidential opposition. As we saw when President Trump vetoed resolutions regarding conflict in Yemen (2019) and with Iran (2020), overriding a veto is a high bar.

In order to remedy these flaws, and create some guardrails that could prevent the United States from inadvertently sliding into war, Congress should reclaim its war powers prerogatives by taking two key steps.

AUMF Reform

Part of the solution requires Congress to revisit its approach to use of force authorizations. The continuation in force of AUMFs for decades is an invitation for overreaching by the executive branch – particularly when those authorizations (like the 2001 AUMF) are interpreted to afford broad discretion to the president to determine the enemy against whom force may be used.

As discussed here and here, Congress appears poised to repeal the 2002 AUMF. But while that is a welcome step, the Biden administration is not currently relying on that statute as the sole source of authority for any ongoing operations, and is not relying on it at all for these strikes against “Iran-backed militia groups” (who are clearly not covered by that authorization). So this is more an exercise in good legal hygiene than a meaningful step to grapple with the scope of ongoing conflict. In order to have a say on current U.S. military operations in Iraq, Syria, and quite a few other countries, Congress should go further and reform the 2001 AUMF, replacing it with a statute that at a minimum defines and limits the enemies it covers, the countries in which it permits operations, the troops’ mission, and a date no more than two or three years in the future by which it must be reauthorized.

This does not mean that the United States should or must end its fight against ISIS. As a practical matter, neither Congress nor the administration will agree to terminate the 2001 AUMF without a replacement vehicle in the wings that would cover the counter-ISIS mission. Still, if the executive branch wants to use force against ISIS in Iraq and Syria, it should make its case to the legislative branch and have an open debate over it, to ensure that as much pertinent information is brought to bear as possible and that the elected representatives of the American people in both political branches support continued U.S. engagement in that war. If doing so will foreseeably require ongoing hostilities with Iran-backed paramilitary forces, and possibly Iran itself, it should make the case for that as well and seek specific authority for such hostilities.

Resurrecting the 1973 War Powers Resolution

While the WPR lost much of its bite when the Supreme Court ruled that a concurrent resolution of disapproval would not be binding, that’s only one way the statute has been degraded. As described here, administrations of both parties have found loophole after loophole to get around its requirements.

But there are moves Congress could make to recover ground that it has lost. Perhaps most important, Congress retains a key power, perhaps the power to compel the termination of unauthorized hostilities: the power of the purse. It is worth remembering that the bigger contribution to terminating U.S. hostilities in Vietnam came not through the 1971 repeal of its statutory authorization, the Gulf of Tonkin Resolution, but through subsequent congressional action prohibiting the use of any funds for combat operations.

Amending the WPR to include an automatic funding cutoff after a specified period of time, leaving a buffer for missions to wind down responsibly, would provide Congress a potent instrument to terminate hostilities. It would “flip the script” from the status quo, whereby congressional inaction enables hostilities to continue. In contrast, under a regime of an automatic funding cut off, Congress would have to affirmatively act in order for hostilities to continue. Executive branch officials would likely think twice before authorizing the expenditure of unappropriated funds to support hostilities in light of the criminal penalties imposed by the Anti-Deficiency Act. Such a funding cutoff would thus require the executive branch to convince Congress that the expenditure of U.S. blood and treasure was justified and in doing so expose the executive branch’s proposals to public scrutiny and debate.

An automatic funds cutoff would also influence the conduct of the executive branch on the front end. If the President faced the credible threat that he or she would be forced to remove U.S. armed forces from hostilities, he or she would likely be more cautious about placing them in harm’s way to begin with.

Other aspects of the WPR need to be tightened as well. Some suggestions for doing so are set forth here [and here] – including to shorten the 60-day window that the statute currently gives the president to obtain authorization, lend clarity to key undefined terms like “hostilities,” and require more frequent and detailed reporting to Congress on missions that it authorizes.


It is unclear whether the pattern of strikes and counterstrikes between the United States and Iran-backed groups in Syria and Iraq will expand into something bigger. What seems clearer is that the executive branch should not by itself be assessing that risk, weighing it against the claimed benefits of U.S. troop presence in the region, or making decisions that could lead the U.S. into a wider conflict. Congress has a crucial role to play in this process. But to do so, it will need to begin rebuilding the war powers guardrails it has neglected for too long.


Image: Getty