Editor’s note: This article is the first in a new series on the National Defense Authorization Act (NDAA) for Fiscal Year 2023.

On December 15, the Senate voted 83 to 11 for the National Defense Authorization Act (NDAA) for Fiscal Year 2023 sending the legislation to President Biden for his signature. From the perspective of reasserting its prerogatives on war and peace, this 4408-page legislation is notable for what it does not include: a repeal of the 2002 Authorization for the Use of Military Force Against Iraq (2002 AUMF). The provisions that were included in the NDAA are, at best, a mixed bag from the standpoint of winding down the United States’ forever wars despite national leaders of both parties having proclaimed that is what they want to do.

The Zombie Iraq AUMF Staggers On

Congress missed yet another opportunity to repeal the twenty-year-old 2002 AUMF, a war authorization that long ago outlived its purpose. Originally enacted to authorize the use of force to confront Saddam Hussein, over the past two decades this AUMF has repeatedly been invoked by the past three administrations to claim it as a basis to fight new enemies. As recounted by Scott Anderson (here and here), successive administrations 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, Iran-backed militias, and even to attack Iran itself in the 2020 strike on Iranian General Qasem Soleimani. This last use of force, justified by Trump administration on the basis of the Iraq war authorization and Article II of the Constitution, nearly precipitated a broader conflict with Iran, when Iran retaliated with a ballistic missile attack on U.S. troops at Al Assad airbase in Iraq which resulted in traumatic brain injuries for over 100 troops but miraculously no fatalities.

After years of efforts by legislators such as Rep. Barbara Lee (D-CA-13) and Sens. Tim Kaine (D-VA) and Todd Young (R-IN), at last the stars had seemingly aligned to dispatch this outdated AUMF. The Biden administration endorsed repeal of the war authorization, explaining that “no ongoing military activities…rely solely on the 2002 AUMF as a domestic legal basis.” In June 2021, the House passed Rep. Lee’s 2002 AUMF repeal bill by a vote of 268 to 161, including 49 Republicans and this past July, the House adopted that bill’s operative text as an amendment to its version of the NDAA. In the Senate, the Foreign Relations Committee approved a resolution introduced by Sens. Kaine and Young rescinding the authorization (along with the 1991 Gulf War AUMF). Kaine and Young assembled a filibuster proof, bipartisan coalition in support of repeal, including 11 Republican cosponsors of their bill. An additional 12th Republican, Sen. Rob Portman (R-OH), voted for the bill to advance out of committee. Following the committee vote, Senate Majority Leader Chuck Schumer (D-NY) gave remarks on the Senate floor, saying “I strongly and fully support repealing the 2002 authorization for the use of military force in Iraq” and pledging to hold a vote on the matter.

And yet, at the 11th hour, the repeal of the 2002 AUMF was not included in the final compromise version of the NDAA. The reasons for this omission include both procedural and substantive elements. From a procedural perspective, Sens. Kaine and Young were, for a second year running, deprived of the opportunity to attach their AUMF repeal bill to the Senate version of the NDAA. They filed their bill as an NDAA amendment. However, in a repeat of last year’s NDAA process, the Senate failed to hold votes on any individual amendments to the bill, leaving the Kaine-Young AUMF repeal amendment in the dust.

Had this amendment received a vote, it would have likely passed and resulted in the inclusion of identical 2002 AUMF repeal language in both the Senate and House versions of the NDAA. Removing this language from both bills would have been a significant challenge and the likelihood of its inclusion in the final NDAA would have been high. Instead, despite the strong bipartisan and bicameral support for repeal of the 2002 AUMF, with only the House NDAA including a provision to rescind the authorization, the fate of repeal was left to a few key negotiators of the final defense policy bill.

One or more of the negotiators might have taken the view that Senate Minority Leader Mitch McConnell (R-KY) expressed in remarks on the Senate floor last year, that repealing the 2002 AUMF would be “reckless” and would remove “authorities for U.S. forces [in Iraq] to defend themselves from a variety of real, exigent threats.” Yet this sentiment remains hard to square between the Biden administration’s repeated confirmation that the 2002 authorization is not needed for any ongoing operations and the president’s Article II constitutional prerogative to use force in self-defense against an attack.

Repealing the 2002 AUMF is important not primarily as a matter of legislative hygiene, but to guard against the future misuse of this tool. Indeed, we have come close to the brink of an undemocratic resort to large-scale war with this AUMF before. Although Congress voted on the AUMF in 2002 to authorize the use of force against Iraq, the Trump administration used the legislation to nearly start a war with a different country, Iran. Despite bipartisan majorities in both houses of Congress taking the position that the 2002 AUMF does not authorize the use of force against Iran, it is entirely plausible that a future, more hawkish administration will again cite this AUMF for exactly that purpose.

Secret Military Partners and the Removal of a Provision on “Collective Self-Defense”

 The “collective self-defense” of partner forces has played an underappreciated role in expanding the scope of the U.S. war on terror and stretching the executive branch’s interpretation of its legal authorities to use force. As described in a report by the International Crisis Group (where one of us works), collective self-defense strikes in Somalia resulted in the United States going to war against Al Shabaab as a group rather than merely targeting a handful of Al Shabaab members who also belonged to Al Qaeda. In Somalia, collective self-defense has continued to be invoked for strikes enabling offensive operations by partner forces. The Trump administration also justified strikes against Iran-backed groups in Syria on this basis, leading to pointed questions from Sen. Kaine about the domestic (and international) legal basis for uses of collective self-defense and partner forces.

Unfortunately, the answers to those questions are not publicly available. Nor is the full list of such partner forces. Based on press releases from U.S. Africa Command announcing strikes in Somalia, we do know that at least in Somalia, partner forces are designated by the combatant commander (a four-star general).

In order to rein in the use of force on the basis of collective self-defense, the Senate Armed Services Committee passed a provision (Section 1044) in its version of the NDAA that would have prohibited anyone below the Secretary of Defense from designating partner forces eligible for “collective self-defense.” The Biden administration, in its statement of administration policy, “strongly oppose[d] section 1044,” arguing that “[t]he authority to defend foreign partner forces and individuals is an inherent and critical component of combined military operations…Prohibiting the President and the Secretary of Defense from delegating this authority to someone below the Secretary would constrain the Department’s ability to provide timely support to emerging situations and operations and to critical allies and partners, and could compromise U.S. personnel, our strategic interests, and foreign partner forces.”

Ultimately, this provision restricting the designation of partner forces was excluded from the compromise NDAA.

Maintaining the Prison at Guantanamo

 Not only did Congress duck opportunities to curtail the war powers of the executive branch, it acted affirmatively to constrain the President’s own ability to wind down one element of the United States’ twenty-year war on terror: the detention of individuals designated as enemy belligerents or combatants at Guantanamo Bay, Cuba. For another year, Congress extended restrictions on the use of funds: for the transfer or release of detainees (Sec. 1031), the construction of an alternative detention facility in the United States (Sec. 1032), the transfer of detainees to certain countries (Sec. 1033), and the closure of Guantanamo (Sec. 1034). Moreover, Congress added Afghanistan to the list of countries (Libya, Somalia, Syria, and Yemen) to which detainee transfers are prohibited (Sec. 1033).

Although none of these restrictions are insurmountable hurdles to the Biden administration’s ongoing efforts to further whittle down the remaining detainee population at Guantanamo, none of them are helpful.

A Silver Lining on Civilian Casualties

With a number of discrete provisions, Congress did make progress around the margins on efforts to better understand, prevent, and compensate for civilian harm caused by the United States.

In order to better comprehend past U.S. targeting practices and civilian casualties over the course of the twenty-year war on terror, section 1067 requires the Pentagon to contract with a federally funded research and development center to develop an independent report on U.S. military practices regarding distinguishing between combatants and civilians. Such an independent report could also circumvent the glib responses from the Pentagon to earlier requirements to define “combatant” and “non-combatant” for the purposes of civilian casualty assessments. Despite prior legislative mandates, DoD’s recent reports to Congress on civilian casualties have not defined those terms but simply linked to DoD’s Law of War Manual which also does not define them with any degree of precision. An independent report focusing on both pre-strike and post-strike definitions and assessments  helps avoid the problem of the Pentagon grading its own homework or spinning a tale for Congress.

In another noteworthy development, following years of reports – from both independent investigators as well as those contracted by the U.S. government – of deficiencies in DoD’s efforts to mitigate and respond to civilian harm from U.S. military operations, section 1082 requires the establishment of a Civilian Protection Center of Excellence 90 days after enactment. The provision codifies and supports the new center, which DoD committed to creating in January. The center will serve as a central hub for efforts concerning civilian casualties and other civilian harm from operations involving the U.S. military, including developing guidance to reduce civilian harm and making recommendations for training to prevent and properly investigate civilian harm incidents. The NDAA also allocates $25 million to implement DoD’s recently released Civilian Harm Mitigation and Response Action Plan (CHMRAP) and extends for a decade, authority and funding for ex gratia payments to civilian victims and survivors of U.S military operations.


Particularly over the last 20 years, Congress has often ceded and the Executive Branch has arrogated the power to decide when, where, and against whom the United States goes to war. Much of that now done in secret. Unfortunately, the FY23 NDAA largely maintains this pattern. But to see this NDAA as reflecting a congressional endorsement of the status quo would miss the full picture. Bipartisan support to rebalance the constitutional division of war powers has continued to grow, with strong majorities in both the House and Senate backing repeal of the 2002 AUMF for instance.

Several opportunities to achieve this repeal before the year’s end still remain. Senate Majority Leader Chuck Schumer could fulfill his commitment and bring the Kaine-Young bill to the Senate floor for a vote. House Speaker Nancy Pelosi has been a strong supporter of 2002 AUMF repeal and would very likely take up the bill in the House, where it would almost certainly pass fairly swiftly. Sen. Schumer could also hold a vote on Rep. Barbara Lee’s 2002 AUMF repeal bill, which could go straight to President Biden’s desk once passed. To fully mirror the Kaine-Young bill, Schumer could also bring to the floor H.R. 3261, Rep. Abigail Spanberger’s 1991 Gulf War AUMF repeal bill, which the House passed last June. As a third option, a 2002 AUMF repeal provision could be included in the appropriations omnibus package, which negotiators are currently working to finalize. Rep. Lee attached this provision to the Department of Defense Appropriations bill in June and it could be retained in the final spending package.

When the 118th Congress begins, it will do so with bipartisan majorities in both chambers in support of 2002 AUMF repeal and a supportive White House. Yet, it remains unclear whether and to what extent a Republican controlled House will seek to check the President’s war powers or hold his feet to the fire by increasing congressional oversight and public transparency over U.S. wars, beyond the already promised scrutiny of the U.S. withdrawal from Afghanistan.

Because of this uncertain future, Congress should strike now while the iron is hot during the lame duck session and at long last exercise its prerogative to repeal the 2002 AUMF. There’s a lot more that Congress needs to do to reclaim its constitutional responsibilities for authorizing and overseeing the use of force but it would be well advised to start with the low hanging fruit. Failure to do so sends the wrong signal. Congress now has the chance to repeal the 2002 AUMF. It should seize it.

IMAGE: U.S. Soldiers of the 663rd Ordnance Company, 242nd Ordnance Battalion, drive military vehicles to the explosives range at Al Asad Air Base, Iraq (U.S. Army photo by Spc. Derek Mustard)