The House Tackles Zombie War Authorizations: Possibilities and Perils
The House Tackles Zombie War Authorizations: Possibilities and Perils
Op-Ed / United States 11 minutes

The House Tackles Zombie War Authorizations: Possibilities and Perils

The U.S. Congress is trying to reassert itself after more than two decades of acquiescence to executive branch overreach on matters of war and peace. Among other recent developments, the House of Representatives is preparing to grapple with repealing and reforming a number of outdated war authorizations. Congress has an opportunity to reclaim some of its constitutional authority on the use of force, but it will need to avoid pitfalls in the process. For its part, the Biden administration should work in earnest with Congress on reform, bearing in mind that successor administrations may not use broad grants of authority judiciously. Although caution is warranted given how often such reform efforts have sputtered in the past, there is also cause for guarded optimism as both political parties put forth a notional path to durably constraining America’s “forever wars.”  

Zombie War Resolutions

Four decades-old war resolutions remain on the books despite have long outlived their original purposes.

Iraq AUMFs

In March, the Senate voted by 66 to 30 in support of a joint resolution introduced by Senator Tim Kaine (D-VA) to repeal the 1991 and 2002 authorizations for the Gulf and Iraq Wars respectively. This move is supported by the Biden administration, primarily because the Pentagon does not need either authorization for any current U.S. military operations. 

The repeal of these Iraq authorizations nonetheless could have practical consequences as it removes the potential that these measures could be misused to justify future wars. This concern is hardly theoretical, as both war authorizations have been stretched far beyond their original intent by administrations of both parties. 

For example, for over a decade after the Gulf War, the executive branch cited the 1991 AUMF as authorizing the enforcement of “no-fly zones” over northern and southern Iraq. The executive branch’s legal argument elided the fact that the United Nations (U.N.) Security Council resolutions that formed the purported basis for the no-fly zones were not among those that the 1991 AUMF authorized the president to enforce. (Further, the U.N. Security Council Resolution that the Bush administration claimed to implement with the no-fly zone, Resolution 688,did not in fact provide authority for the use of force as a matter of international law.) (See Letter to Congressional Leaders Reporting on Iraq’s Compliance with United Nations Security Council Resolutions, 2 Pub. Papers of Pres. George Bush 1574, 1574-75, Sept. 16, 1992)

Similarly, multiple presidents have repurposed the 2002 Iraq AUMF. Originally enacted to authorize the use of force against former Iraqi President Saddam Hussein, this AUMF has been invoked by the past three U.S. administrations as a purported legal basis to fight entities that ostensibly posed a threat to Iraq. As recounted by Scott Anderson (here and here), successive presidents have relied upon the 2002 AUMF, often (and recently almost always) in conjunction with other legal authorities, to fight Shia armed groups such as the Mahdi Army, al-Qaeda in Iraq, ISIS, Iranian-backed militias.  The Trump administration also relied on the 2002 AUMF as part of its legal justification for the 2020 drone strike that killed and Iranian General Qasem Soleimani and Deputy Chief of the Iraqi Popular Mobilization Forces Abu Mahdi al-Muhandis in Iraq.  Iran retaliated by launching a ballistic missile attack on U.S. troops at Al Assad airbase in Iraq which resulted in traumatic brain injuries for over 100 troops, though the outcome could have been even worse, including a broader conflict with Iran. 

Although the use of the 2002 AUMF to attack Iran has been critiqued by former senior U.S. national security lawyers and rejected by bipartisan majorities in both houses of Congress, the Trump administration nonetheless established a dangerous precedent. The repeal of these outdated Iraq authorizations is thus more than a matter of mere legislative hygiene.  The 2002 AUMF remains susceptible to future abuse, specifically as purported authority to attack Iran and Iranian-backed groups.  This in fact was the reason that some Republican Senators have opposed its repeal

2001 AUMF

In contrast to the 1991 and 2002 authorizations which the executive branch does not require for ongoing military operations, the U.S. military continues to rely upon the 2001 AUMF–the principal statutory authority for the war on terror–for a range of activities.  As described in this report by the International Crisis Group (where I work), administrations of both parties have unilaterally stretched an authority originally focused on those responsible for the 9/11 attacks (al-Qaeda) and those that harbored them (the Taliban) to argue that it applies to a range of groups on multiple continents. The expansion of the scope of the 2001 AUMF was enabled in part through creative lawyering within the executive branch, including the concoction of the concept of “associated forces” whereby the war authorization was deemed to apply to new groups that were allied with al-Qaeda and the Taliban. It was through such legal innovations that, for example, the Obama administration deemed the 2001 AUMF to apply to al-Shabaab as an associated force of al-Qaeda, even though al-Shabaab did not exist at the time of the 9/11 attacks.

In an August 2017 letter to Congress, then Deputy Secretary of State John Sullivan described the range of activities the U.S. military relied upon the 2001 AUMF at that time.

The 2001 AUMF provides statutory authority for ongoing U.S. military operations against the following individuals and groups: al-Qa’ida; the Taliban; certain other terrorist or insurgent groups affiliated with al-Qa’ida or the Taliban in Afghanistan; al-Qa’ida in the Arabian Peninsula; al-Shabaab; individuals in Libya who are part of al-Qa’ida; al-Qa’ida in Syria; and ISIS.

The 2001 AUMF also provides statutory authority for the United States to detain those persons who were part of, or substantially supported, Taliban or al-Qa’ida forces or associated forces that are engaged in hostilities against the United States or its coalition partners, including any person who has committed a belligerent act, or has directly supported hostilities, in aid of such enemy armed forces. During the past decade, the United States has detained individuals pursuant to the authority of the 2001 AUMF in Afghanistan, in Iraq, temporarily at sea, and at the Guantanamo Bay detention facility. The United States continues to detain 41 individuals at Guantanamo Bay.


Following the U.S. withdrawal from Afghanistan in 2021, the U.S. military has continued to use military force under the 2001 AUMF at least in Iraq, Syria and Somalia. Notably, measured by airstrikes, the U.S. conflict with al-Shabaab—a group that had nothing to do with the 9/11 attacks—is now the most intense fight of the U.S. “war on terror.” Known military operations are only part of the story, as the full list of groups to who could potentially be targeted under the 2001 AUMF (at least in the view of the U.S. executive branch) remains classified. Additionally, the United States continues to detain 30 individuals at Guantánamo Bay indefinitely under the laws of war under the domestic authority of the AUMF. 

Notwithstanding that the United States has transitioned into what might be described as “GWOT-lite” –conducting fewer airstrikes in fewer countries than during the height of the war on terror – the need for AUMF reform remains. President Biden’s decision to dial back the war on terror can easily be undone by his successor so long as the statutory framework endures. The executive branch of both parties has been able to unilaterally stretch the scope of the 2001 AUMF for more than two decades due to the underlying malleability of this authorization. 

The broad contours of what an updated or replacement for the 2001 AUMF should look like are clear. Any reformed war authorization should:

  • Explicitly specify against whom force may be used and bar the unilateral addition of further groups or “associated forces” by the executive branch;
  • Specify in which countries force may be used (such geographic limitations are especially important given the proliferation of ISIS affiliates, particularly in Africa); and 
  • Contain a sunset provision at which time the authorization expires if not reauthorized. A sunset will also be important to prevent runaway assertions of authority, ensure political accountability, and create events where the costs and consequences of war must be periodically discussed before the American people.   

(For example, see this framework from Tess Bridgeman, Ryan Goodman, Stephen Pomper, and Steve Vladeck.)  

That said, within Congress there is little consensus on whether the 2001 AUMF should be repealed and, if so, whether and what should replace it.  Many members, if not satisfied with the status quo, are content not to have to take a difficult vote on such a weighty matter of war and peace. Other members, in both parties, would prefer simply to repeal but not replace the AUMF. Another group would prefer to craft a new AUMF tailored to the groups the US already claims the right to be fighting under the current AUMF. A final group of members would like to expand the scope of the current authorization to target, not only Sunni jihadi groups, but also to provide explicit statutory authority to target Iran-backed groups in Iraq and Syria, and perhaps even Iran itself.

For its part, the Biden administration has offered rhetorical support for an updated war authorization, but the few details it has shared of its preferences suggest it wants to replace the current AUMF with an equally expansive measure.  During a March 2022 hearing before the House Foreign Affairs Committee, then Deputy Secretary of State Wendy Sherman stated that:

[A]ny updated or replacement AUMF, Congress should consider establishing mechanisms and standards, that address how it will apply to terrorist groups beyond those that may be identified by name in the text of an AUMF, and to include periodic review of the groups that are subject to the use of force and the locations where force is to be used.This statement suggests that the administration wishes to retain the ability to unilaterally add additional groups to the scope of any new AUMF.  


Further the Deputy Secretary stated that the administration opposed a sunset provision in any new authorization, “including because we’re concerned about the signal it would send to our adversaries. (Notably, in 2015, the Obama administration backed an ISIS-specific AUMF containing a three-year sunset provision. That war authorization failed to gain sufficient support in Congress.) 

Overall, the Biden administration seems content with the authority it believes the 2001 AUMF provides and is looking for similarly expansive authority in any replacement. 

1957 Middle East Resolution

Finally, and old enough for retirement, there is the 1957 Middle East Resolution which provides:

[T]he United States regards as vital to the national interest and world peace the preservation of the independence and integrity of the nations of the Middle East. To this end, if the President determines the necessity thereof, the United States is prepared to use armed forces to assist any such nation or group of such nations requesting assistance against armed aggression from any country controlled by international communism


As Matt Waxman has noted, this resolution is framed in declaratory terms–“the United States is prepared to use armed forces”–rather than in terms of authorization granting the President additional power.  Although President Eisenhower would deploy 14,000 troops to Lebanon the next year, neither he nor any subsequent U.S. president would invoke this resolution in connection with the use of force.  

Potential Pitfalls for Reform in the House

The current efforts in the House to tackle outdated war authorizations are led by representatives Ken Buck (R-CO) and Dean Phillips (D-MN) tapped by their respective party leadership on the House Foreign Affairs Committee.  In repealing and updating these use of force authorizations, the House will need to avoid several procedural and substantive pitfalls.

As a procedural matter, the old legislation should be addressed through three separate resolutions. 

  • First, as the Senate has already passed a clean repeal of the 1991 & 2002 AUMFs, the House should vote on that resolution. 
  • Second, the House should move forward with a standalone repeal of the 1957 Middle East resolution. 
  • Finally, the House should address the most contentious legislative project, reforming the 2001 AUMF, separately given the current lack of consensus on the content of any replacement. 

The alternative approach of bundling the repeal and replacement of these measures together in a single omnibus resolution likely would doom the reform efforts, particularly given the disagreement on what, if anything, should replace the 2001 AUMF.

Substantively, any replacement for the 2001 AUMF should avoid merely reproducing its flaws.  A new resolution should authorize the use of force against a named set of entities and only those entities–it should bar the executive branch from unilaterally expanding the scope of the authorization including through the concept of “associated forces.”  To do the opposite by codifying this claimed authority – as the administration has requested – could risk making it an indelible feature of the war powers landscape, and dangerously curb Congress’s capacity to act as meaningful check on executive branch waging war. 

If the executive branch believes it requires additional authority to use force against a new group not listed in the authorization, it should return to Congress and make its case. To address potentially emergent threats, a replacement resolution could, as a compromise, provide for expedited procedures in Congress to add either additional groups or expand the geographic scope of the authorization. Of course, the president always retains the power under Article II of the Constitution to use limited force to “repel sudden attacks” against the United States. Thus, the president would be able to defend the United States while Congress decided whether to grant statutory authority for broader and longer military action. This is the current scheme under Section 6 of the War Powers Resolution. Congress should not repeat the mistake of the 2001 AUMF by delegating to the president the unilateral power to decide against whom the country is at non-defensive war.

Further, any new war authorization should reflect due caution about giving the executive branch authority it neither seeks nor wants when it comes to the use of force.  A replacement for the 2001 AUMF should not provide statutory authority for the use of force against Iranian-backed militia groups in Iraq or Syria, much less Iran itself.  Even if such an authority is regarded as “just in case” of contingencies, a use of force authorization against militias could spur rather than deter further attacks on U.S. personnel in Iraq and Syria, with potentially grave escalatory implications. To be sure, the Biden administration has already been engaging the militias, relying–perhaps unconvincingly–on Article II of the Constitution to use force against these militias in purported defense of U.S. forces. Even if these Article II-based justifications are problematic–as Tess Bridgeman and I have argued here–reliance on a strained legal argument is less harmful than Congress delegating broad authority for an unnecessary conflict.  Finally, as a matter of practical politics, including authority for the use of force against these groups would likely doom the prospects of any replacement for the 2001 AUMF.   

* * *

Reflecting a combination of bipartisan fatigue with the United States’ “forever wars,” a skepticism of the utility of military force, and a desire to reassert Congress’s constitutional prerogatives, the legislative branch is taking action, albeit halting, to repeal and reform war authorizations.  In doing so, it will need to skirt certain snags that could either derail legislation or repeat the mistake of delegating poorly constrained war-making authority to the president. The Biden administration should seize the opportunity to work with Congress in earnest to reform the authorization for the war on terror, mindful of its commitments to ease the United States out of legacy conflicts, and the risk that a future president may not use broad authority in a restrained or wise fashion.   

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