September 1, 2021
The United States, over the last two decades, has already spent and the Biden administration has requested about $5.8 trillion in reaction to the 9/11 attacks.  This includes the estimated direct and indirect costs of spending in the United States post-9/11 war zones, homeland security efforts for counterterrorism, and interest payments on war borrowing. Costs for medical care and disability payments for veterans is the largest long-term expense of the post-9/11 wars.
As research by Linda Bilmes shows, future medical care and disability payments for veterans, over the next decades, will likely exceed $2.2 trillion in federal spending. Including estimate future costs for veteran’s care, the total budgetary costs and future obligations of the post-9/11 wars is thus about $8 trillion in current dollars.
Of course, this report on the budgetary impact of the counterterror wars is not the full story of the costs and consequences of the post-9/11 wars. Behind every one of these numbers are people—inspecting containers for possible weapons of mass destruction, deploying overseas, and caring for veterans. Included in these numbers is an acknowledgment of death: behind the decimal point of estimated total costs, $704 million has been spent on death gratuities for the survivors of the 7,040 men and women in the military who were killed in the war zones. And there is also money the U.S. has provided in compensation to the civilians injured and killed in these wars.
This estimate includes the amount requested in May 2021 by the Biden administration for FY2022. It does not include the additional money members of Congress have suggested that they may appropriate for the DOD for the FY2022 request.
Nor does it include all the money provided for humanitarian assistance and economic development aid in Afghanistan and Iraq. It does not include the future costs of interest payments on borrowing to pay for the post-9/11 wars after FY2023. It does not include spending by the dozens of United States allies, including Australia, Britain, Canada, Denmark, Italy, the Netherlands, Romania, Germany and France. If the U.S. had not had the support of those allies, it would likely have spent more on those wars (and arguably taken more casualties). This estimate also does not include spending by state and local governments within the U.S. for counterterrorism or services for post-9/11 war veterans.
There has been no single U.S. government estimate for the total costs of the post-9/11 wars. There are partial accounts of post-9/11 war costs. For example, starting in FY2017, the Department of Defense (DOD) has been required to report the estimated costs of the wars in Afghanistan, Iraq and Syria to each taxpayer and since then, the DOD regularly produces a tabulation of the “Estimated Cost to Each Taxpayer for the Wars in Afghanistan and Iraq.” In March of 2021, the Department of Defense concluded in their most recent public estimate that emergency/overseas contingency operations (OCO) spending for the wars in Iraq, Syria, and Afghanistan cost a total of $1.596 trillion, or $8,094 per taxpayer through FY 2020. However, as the DOD notes, “these amounts exclude non-Department of Defense classified programs.” On August 16, 2021, as the U.S. exited Afghanistan, President Biden said, “We spent over a trillion dollars.” This is, of course, correct, — if we focus only on what the DOD was appropriated for the Afghanistan war and leave out other major costs, perhaps most importantly, the costs of caring for the post-9/11 war veterans.
One of the major purposes of the Costs of War Project has been to provide a more comprehensive view of federal war appropriations and expenses, to clarify the types of budgetary costs of the U.S. post-9/11 wars, how the post-9/11 operations have been funded, and the long-term implications of past and current operations on spending. The costs of the post-9/11 wars include direct appropriations for operations in the war zones, additional expenses incurred by the Department of Defense in the “base” military budget, spending to defend the “homeland,” and spending for veteran’s medical and disability care. Moreover, the costs associated with the wars include the interest payments made on borrowing to pay for the wars. Further, because the U.S. continues other counterterror operations, and the costs of caring for veterans and interest on borrowing will continue, the budgetary costs do not end when the fighting in the major war zones stops.
The full report is at <<watson.brown.edu/costsofwar>>
 Neta C. Crawford is a Professor and Chair of the Department of Political Science at Boston University and a Co-Director of the Costs of War Project.
 All the costs reported here are in current dollars.
 For instance, this accounting of State Department spending does not include more than a billion dollars in USAID and State Department funds appropriated since 2002 for Development Assistance, Global Health Programs, Human Rights and Democracy, and Transition Initiatives in Afghanistan.
 See Jason W. Davidson. (2021). “The Costs of War to United States Allies Since 9/11,” Costs of War Project, https://watson.brown.edu/costsofwar/files/cow/imce/papers/2021/Davidson_AlliesCostsofWar_Final.pdf.
 Public Law 114-328, the National Defense Authorization Act for Fiscal Year 2017.
 Department of Defense, “Estimated Costs to Each U.S. Taxpayer of Each of the Wars in Afghanistan, Iraq and Syria,” March 2021. https://comptroller.defense.gov/Portals/45/documents/Section1090Reports/Estimated_Cost_to_Each_U.S._ Taxpayer_of_Each_of_the_Wars_in_Afghanistan,_Iraq_and_Syria_dated_March_2021.pdf.
 President Joseph Biden. (August 16, 2021). “Read the Full Transcript of President Biden’s Remarks on Afghanistan,” The New York Times. https://www.nytimes.com/2021/08/16/us/politics/biden-taliban- afghanistan-speech.html.