Armed Conflict Executive Branch Foreign Relations & International Law

Seven Observations on WPR Letters Issued Since 2001

Matt Gluck
Tuesday, November 7, 2023, 1:06 PM
Identifying seven takeaways from the War Powers Resolution letters on its 50th birthday.
US Army soldiers in a small village in northern Iraq during Operation Iraqi Freedom, December 2003. (The U.S. National Archives/SSGT Jeffrey A. Wolfe, USA,; Public Domain,

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The past four presidents have issued a total of 106 publicly available War Powers Resolution (WPR) letters. The letters, all of which are listed with links at the end of this article, provide detailed descriptions of U.S. military operations around the globe since Jan. 20, 2001. What follows is not a comprehensive description of the WPR letters but, instead, seven takeaways from the letters and notable revelations from additional, non-WPR, war powers reporting. 

1. Consistency of “Consolidated” WPR Letters

The 106 letters include 38 “supplemental consolidated reports” that presidents have issued biannually since 2004. Each consolidated report describes all U.S. operations reportable under the WPR during a six-month period. (Certain types of operations, such as covert actions, need not be reported under the War Powers Act because they are outside the scope of the statute.) There is one exception to this consistent biannual reporting: It appears that President Donald Trump broke with executive branch practice during his time in office and issued only one consolidated report in 2020. It’s unclear what prevented the Trump administration from issuing a second consolidated report in 2020.

2. Treatment of Detainees at Guantanamo Bay

President George W. Bush first referenced the establishment of Guantanamo Bay and the detention of 300 detainees at the center in a March 2002 WPR letter. In that letter, he wrote, “[The detainees are] being treated humanely and, to the extent appropriate and consistent with military necessity, in a manner consistent with the principles of the Geneva Conventions of 1949.” That same language remained in Bush’s next two WPR letters referencing Guantanamo Bay, sent to Congress in September 2002 and March 2003—though the September 2002 letter referenced the “Geneva Convention” instead of the “Geneva Conventions” (emphasis added). However, Bush removed that language from his discussion of Guantanamo Bay in a September 2003 letter and from the discussion of Guantanamo Bay in the rest of his WPR letters.

President Barack Obama also did not mention the treatment of Guantanamo Bay detainees in the first eight letters in which he discussed the detention facility. This changed in June 2013, when Obama wrote, “Combat-equipped forces, deployed since January 2002 to the Naval Base in Guantanamo Bay, Cuba, continue to conduct humane and secure detention operations for the approximately 166 detainees at Guantanamo Bay” (emphasis added). In the rest of his WPR letters, Obama used the word “humane” to describe detention practices at Guantanamo Bay. The same descriptor remained in the rest of Obama’s consolidated letters discussing Guantanamo Bay, and it has been included in all of the consolidated letters referencing the facility issued by Presidents Trump and Joe Biden, whose most recent consolidated letter notes: “United States Armed Forces continue to conduct humane and secure detention operations for detainees held at Guantanamo Bay.”

It’s not clear what caused Bush to remove the words “treated humanely” in September 2003 or what led Obama to begin to describe the U.S. detention operations as “humane” in June 2013. In future analysis, it would be worth examining whether these changes in the descriptions of the detention operations reflect an adjustment in policy, a changed legal interpretation, or some other explanation.

3. Consistency of Certain Operations Against al-Qaeda and the Islamic State in Iraq and Syria

The WPR letters reveal that certain core components of the U.S. fight against the Islamic State and al-Qaeda in Iraq and Syria have remained remarkably consistent. According to the WPR letters, three components of this fight remained mostly unchanged from the time they began in the summer of 2014 until the end of 2021. Quoting from Obama’s December 2016 WPR consolidated report:

[1] U.S. Armed Forces are conducting a systematic campaign of airstrikes and other necessary operations against ISIL forces in Iraq and Syria.

[2] United States Armed Forces are also conducting airstrikes and other necessary operations against al-Qa'ida in Syria.

[3] In Iraq, U.S. Armed Forces are advising and coordinating with Iraqi forces and providing training, equipment, communications support, intelligence support, and other support to select elements of the Iraqi security forces, including Iraqi Kurdish Peshmerga forces.

Each consolidated report issued through the end of 2021 includes descriptions—sometimes with slight variation—of these three general operations. And beginning with the December 2015 consolidated report, a fourth component was added to the list of consistent operations and remained there, essentially unchanged, for six years: “Small teams of U.S. special operations forces have deployed to Syria to help coordinate U.S. operations with indigenous ground forces conducting operations against ISIL.”

For example, Trump’s last consolidated report issued in June 2020, reads (reordered for the sake of comparison):

[1-2] United States Armed Forces are conducting a systematic campaign of airstrikes and other necessary operations against ISIS forces in Iraq and Syria and against al-Qa'ida in Syria...

[3] ...United States Armed Forces in Iraq continue to advise, coordinate with, and provide support to select elements of the Iraqi security forces, including Iraqi Kurdish security forces. Support to Iraqi security forces includes training, equipment, communications support, and intelligence support...

[4] ...A small presence of United States Armed Forces remains in strategically significant locations in Syria to conduct operations…in partnership with indigenous ground forces, against continuing terrorist threats emanating from Syria.

4. Inconsistent Reporting Methodology of Operations Against the Islamic State

When the United States began fighting the Islamic State in 2014, President Obama appeared to report each individual operation in individual, distinct War Powers Resolution letters. On June 16, 2014, Obama reported the deployment of approximately 275 U.S. military personnel to Iraq to secure the area against the Islamic State. Over the course of approximately four months, Obama sent eight additional letters detailing U.S. operations against the Islamic State. These covered airstrikes, humanitarian operations, and the deployment of additional forces, among other activities. On Sept. 23, however, Obama’s detailed reporting suddenly stopped. After Obama’s report on Sept. 23, he began to report operations against the Islamic State in his consolidated reports with noticeably scant detail about individual operations. 

The Obama administration did not provide an explanation for its shift in reporting. Jack Goldsmith, however, laid out a compelling theory as to why on Lawfare. As pointed out by Goldsmith, the first eight letters referencing operations against the Islamic State cited the president’s Article II power as the authority for the operations. Describing these military activities as distinct operations for approximately four months allowed the executive branch to avoid the requirement under the WPR for congressional approval of U.S. engagements in hostilities that last more than 60 days. In the ninth letter describing the operations, the administration began to cite the 2001 and 2002 Authorizations for the Use of Military Force (AUMFs)—stopping the 60-day clock that would have been running had the administration framed operations against the Islamic State as one extended fight, as it did following its Sept. 23 letter.

5. Citing the 2001 and 2002 AUMFs

Citations of and references to the 2001 and 2002 AUMFs vary in certain notable ways across the letters.

President Bush wrote in his March 2002 WPR supplemental report on U.S. counterterrorism activities that these operations were “consistent with” the 2001 AUMF. Bush repeated this in the supplemental reports on counterterrorism in September 2002, March 2003, and September 2003. However, Bush curiously removed the claim that these counterterrorism operations were “consistent with” the 2001 AUMF from his March 2004 supplemental consolidated report and from the rest of his letters that referenced counterterrorism operations.

Obama shifted the executive branch’s reliance on the 2001 AUMF in the WPR letters in a few significant ways. In June 2009, Obama wrote that the detention operations at Guantanamo Bay were authorized by the 2001 AUMF, which has remained the claim in every consolidated report issued since. In June 2010, Obama also began to cite the 2001 AUMF—in addition to general statutory authority—in his consolidated reports as authorization for certain unspecified operations, which has also been true of every consolidated report issued since. Obama’s June 2012 consolidated report brought another shift regarding reference to the 2001 AUMF, as he began to cite the statute as specific authorization for detention operations in Afghanistan. He continued to cite the 2001 AUMF for these Afghanistan detention operations until the end of 2014.

President Trump in December 2017 became the first of the four presidents to cite explicitly the 2002 AUMF as statutory authorization for U.S. military activities in a consolidated report. That practice continued in the rest of Trump’s consolidated reports. It’s not clear why Trump did not cite the 2002 AUMF in his first consolidated report issued in June 2017 before citing it in December and in all of the following reports. One possible explanation is that the December 2017 report references the intensification of U.S. military activities targeting the Islamic State—which the Trump administration viewed as authorized under the 2002 AUMF—in Syria, Yemen, and Somalia and the deployment of forces to Lebanon to combat the Islamic State.

6. Classified Annexes

Publicly available WPR letters do not precisely define the nature and scope of U.S. military operations for two primary reasons. First, many of the reports contain a “classified annex.” Beginning with Obama’s report issued in December 2010, each of the consolidated reports submitted biannually have referenced a classified annex that is not publicly available but purports to provide additional information to Congress about U.S. military operations.

There do not appear to be any limits on what can be reported in these classified annexes. In addition to classified annexes within reports, presidents can also issue fully classified letters—which presidents Obama and Trump each did at least once (most recently in reporting the strike that killed Iranian Gen. Qassem Soleimani).

7. General Language

The second primary reason why the letters are not comprehensive is the nonspecific language presidents use in their descriptions of U.S. military operations.

For example, President Bush said in a letter issued on Sept. 24, 2001, that he had “ordered the deployment of various combat-equipped and combat support forces to a number of foreign nations in the Central and Pacific Command areas of operations.” Beginning in 2002, Bush also repeatedly wrote that the U.S. was conducting “maritime interception operations on the high seas” to find and capture terrorists. Similarly, Bush often said that he had deployed forces in a certain region—such as the Horn of Africa—without explicitly naming the countries where U.S. forces were operating. And as Michael Knapp pointed out on Lawfare, Bush referenced operations across several U.S. command areas “in support of those operations [Afghanistan] and of other operations in our global war on terrorism” in every consolidated report issued since March 2004.

As Knapp explains, Obama’s reports—like Bush’s—also include ambiguous language that makes unclear the exact scope of U.S. operations. Obama’s consolidated reports describe deployments “to a number of locations ... in support of those [Afghanistan] and other overseas operations.” And Trump’s consolidated reports also include the nonspecific language of the deployment of U.S. forces “in support of these [Afghanistan] and other overseas operations.” Like consolidated reports issued in prior administrations, Biden’s consolidated letters note the deployment of forces “[i]n support of these and other overseas operations.”

Other War Powers Reporting

War powers reporting does not consist entirely of letters issued “consistent with the War Powers Resolution.”

Most additional publicly available war powers reporting is obligated under two statutes: 50 U.S.C. § 1549, which requires a report “on the legal and policy frameworks for the United States’ use of military force and related national security operations” each year by March 1 and within 30 days after a change is made to the frameworks; and 50 U.S.C. § 1550, which requires a report from the president every six months on military actions taken under the 2001 AUMF. (Both of these sets of reporting obligations were codified on Dec. 20, 2019, but 50 U.S.C. § 1549 was originally enacted in Section 1264 of the Fiscal Year 2018 National Defense Authorization Act (NDAA), and 50 U.S.C. § 1550 was enacted in Section 1285 of the Fiscal Year 2020 NDAA.) The Trump and Biden administrations have not complied fully with these statutes’ reporting obligations, though the Trump administration’s lack of reporting was more egregious. Much of the important information in these reports is in their classified annexes and is therefore not accessible. But some points are worth noting.

In December 2016, the Obama administration issued a “Report on the Legal and Policy Frameworks Guiding the United States’ Use of Military Force and Related National Security Operations,” which precipitated the enactment of at least one of these sets of reporting requirements. In this report, the administration noted that the 2002 AUMF authorizes the use of force against the Islamic State in Iraq and “in certain circumstances” against al-Qaeda and the Islamic State in Syria.

On March 12, 2018, the Trump administration provided Congress with an updated report under § 1549. The report references what appears to be a previously unreported Islamic State attack in Niger against U.S. forces on Dec. 6, 2017. The White House cites two statutes as legal authority for military operations that were not mentioned explicitly in the WPR reports: It says that Sections 1222 and 1223 of the 2018 NDAA authorize military actions in Iraq and Syria, respectively.

In May 2019, President Trump issued a relatively minor update to the legal and policy frameworks, notifying Congress that he was removing a reporting requirement regarding civilian casualties. And in February 2020, the White House released a report to satisfy the legal and policy framework reporting requirements justifying the January 2020 killing of Soleimani. The Trump administration did not publicly release a WPR letter following the killing. Instead, the report provided the administration’s explanation of the interests that motivated the killing and the legal justification for it. It argued the killing was authorized under the president’s Article II power and the 2002 AUMF. In October 2020, the Trump administration also noted in another report that the Iraqi government requested U.S. military assistance in the fight against the Islamic State and that the 2001 AUMF applies to U.S. operations countering the Islamic State in Syria.

Between April 4, 2021, and March 1, 2023, the Biden administration issued three reports on the legal and policy frameworks and one “notice of change” attached to the first report.

The notice of change references “new interim guidance concerning the United States’ use of military force and related national security operations” that Biden had established on Jan. 20, 2021, and clarified on Feb. 19 of that year. The new guidance appears to refer, at least in part, to Biden’s reported decision to require the military and the CIA to obtain authorization from the White House before conducting drone strikes or commando raids outside of conventional battlefield arenas. The first two reports themselves do not include anything substantively new or material.

The third report includes one new and important point. It reveals that the U.S. no longer intends to rely on the Ghani government’s “previously provided consent” for the use of force in Afghanistan to combat terrorist threats in the country. The Biden administration also noted that it maintains the position that it “has the inherent right to use necessary and proportionate force in self-defense to the extent that Afghanistan is unwilling or unable to confront effectively” threats against the United States.

In March 2022, the Biden administration submitted three reports to Congress under 50 U.S.C. § 1550 (the provision concerning reporting on AUMF reliance) at once. Although much is relegated to the classified annexes to these reports, at least two salient points emerge.

The first is the administration’s view that al-Qaeda, the Islamic State, and al Shabaab pose either no threat or a “low” level of threat to the U.S. homeland. It’s worth noting, though, that the administration still believes the Islamic State poses a meaningful threat in Syria and that al Shabaab “poses a high terrorist threat to U.S. interests in Somalia.” Another important point made clear in the report, as articulated by Brian Finucane and Heather Brandon-Smith, is that the administration appears to perceive al-Qaeda in the Indian Subcontinent as part of al-Qaeda in the context of the 2001 AUMF. In contrast, the administration appears to consider Hay’at Tahrir al-Sham (HTS) to be separate from al-Qaeda—which is notable “because the executive branch has regarded HTS’s predecessor organization al Nusra Front to be ‘part of’ al-Qa’ida” with respect to the 2001 AUMF.


The WPR letters linked below do not comprehensively describe U.S. military operations. But they’re worth reading because they illuminate certain aspects of the U.S. military presence around the globe and the authorities underlying military activities. They also shed light on the nature and limitations of congressional mechanisms to promote executive branch accountability in the war powers context.

Publicly Available War Powers Resolution Letters Submitted to Congress in the Past Four Presidential Administrations

Bush’s WPR Letters









Obama’s WPR Letters









Trump’s WPR Letters





Biden’s WPR Letters




Matt Gluck is a research fellow at Lawfare. He holds a BA in government from Dartmouth College.

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