U.S. War Costs, Casualties, and Personnel Levels Since 9/11
link to page 2 
April 18, 2019
U.S. War Costs, Casualties, and Personnel Levels Since 9/11
Seventeen years have passed since the U.S. initiated major
In Iraq and Syria, obligations for war fell with the departure
military operations following the September 11, 2001,
of most U.S. troops in December 2011, but rose again as air
terrorist attacks. In the intervening period, operations first
and ground operations against ISIS intensified. Between
classified as Global War on Terror (GWOT) and later
FY2016 and FY2018, the U.S. obligated an average of $7.2
Overseas Contingency Operations (OCO) have varied in
billion annually for operations in Iraq and Syria.
scope. Though primarily focused on locations in
Afghanistan and Iraq, they have also included territories
DOD Non-War Program Costs
throughout Central and Southeastern Asia, the Middle East,
According to DOD reporting, roughly 12% ($.2 trillion) of
and Africa. This In Focus summarizes major expenditures
all funding appropriated through war-related requests since
on U.S. war operations, reconstruction assistance, troop
9/11 has funded non-war programs. These include
levels and casualties, and ongoing issues for Congress. This
congressional transfers to OCO, funding for the European
analysis narrowly defines war/non-war costs as OCO-
Deterrence Initiative, non-DOD classified programs,
designated appropriated funds associated with overseas
adjustments for (non-GWOT) fuel costs, and Army
operations as designated in DOD’s official “Cost of War
modularity programs (service restructuring).
(CoW)” report. Other observers may define war operations
or costs more broadly (see “Issues for Congress” section).
Use of the OCO Designation
Estimates of the cumulative costs of war are complicated by
Department of Defense War Costs
the use of OCO-designated funds for base budget activities.
Congress has appropriated a total of $1.55 trillion in
Under current law, funding designated for emergencies and
discretionary amounts to the Department of Defense (DOD)
overseas contingencies is not counted under budget limits
for war funding since 9/11, according to DOD reporting.
set annually by congressional budget resolutions. After
(See following section for OCO non-war expenditures.)
passage of the Budget Control Act (BCA) in 2011,
Obligations of those amounts peaked during two surges of
exceeding such budget caps triggers across-the-board cuts
U.S. military activity; first in Iraq in FY2008 ($140 billion),
(sequestration) to agency programs.
and then in Afghanistan in FY2011 ($97 billion).
As a means of complying with the BCA, Congress and the
Figure 1. Iraq and Afghanistan: War Spending and
president have increasingly designated substantial amounts
Troop Levels Since 2008
of funding as OCO to provide for base military activities.
Because of this practice, some argue that OCO has become
a slush fund that obscures the true cost of both war and non-
war spending. Others argue that the OCO designation
affords necessary flexibility to apply funds when and where
needed.
Base and Enduring Requirements
DOD’s FY2020 budget request debuts new OCO funding
categories that identify the requirement for which the
portion of OCO is intended. These requirement categories
include the following:
Source: For costs, DOD “Cost of War,” September 2018; for troop
Direct War Requirements ($25.4 billion; 15%):
levels, FY2020 DOD Comptrol er “Defense Budget Request
Direct combat support and partnership training costs.
Overview.”
OCO for Enduring Requirements ($41.3 billion;
As a percentage of total OCO-designated obligations, the
24%): Indirect operational costs likely to remain even
two conflicts have been roughly equivalent. Obligations for
after GWOT combat operations have ended; also funds
operations primarily in Afghanistan represent 49% ($737
European Deterrence Initiative and Ukraine Security
billion) overall, while those for Iraq represent 51% ($759
Assistance.
billion).
OCO for Base Requirements ($97.9 billion; 56%):
Base funding included to comply with BCA spending
Over the past three years, obligations for war spending have
limits.
averaged $47 billion per year, mostly to fund the operating
Emergency Requirements ($9.2 billion; 5%):
support costs of U.S. forces in and around Afghanistan.
Includes $2 billion in disaster relief and $7.2 billion
Between FY2016-FY2018, the Afghan Security Forces
Fund comprised 9.16% of all obligations for Afghanistan.
intended for construction of southwest border wall.
https://crsreports.congress.gov
U.S. War Costs, Casualties, and Personnel Levels Since 9/11
Non-DOD Reconstruction Costs
Freedom, Operation Inherent Resolve, and Operation New
Congress has appropriated $44.8 billion to non-DOD
Dawn. Troops killed or wounded in operations primarily
agencies (and civilians) since 2002, for reconstruction and
associated with Afghanistan—Operation Enduring Freedom
relief operations in Afghanistan. The largest agency
and Operation Freedom’s Sentinel—represent 38%
involved in the effort has been USAID (54%), which
(22,884) of the remainder.
administers a foreign assistance account called the
Economic Support Fund (ESF). The ESF accounts for $20.5
Though most U.S. war casualties since 9/11 have occurred
billion, or roughly 46% of all non-DOD reconstruction
within the territories of Iraq and Afghanistan, 383 U.S.
assistance directed to Afghanistan.
personnel have died during contingency operations
elsewhere, such as at locations in Africa, South Asia,
For Iraqi reconstruction and relief efforts (2003-2012),
Central Asia, Europe, the United States, the Middle East, or
Congress provided multiple funding streams. Roughly $10
at sea.
billion has been allocated to non-DOD agencies, primarily
USAID and the State Department for the Iraq Relief and
Contractor Casualties
Reconstruction Fund (IRRF) and the ESF.
DOD does not systematically record the deaths or injuries
of U.S. contractors. Data compiled by the Department of
U.S. Troop Levels
Labor suggest that 3,413 civilian employees under contract
Approximately 22,200 troops currently serve in
with the U.S. government for public works or national
Afghanistan (15,000), and Iraq and Syria (7,200). An
defense have been killed in Afghanistan and Iraq in the
additional 65,622 American military and civilian personnel
years since 9/11. An additional 38,953 have sustained
operate in support of broader contingency operations; they
work-related injuries that resulted in four or more lost work
are located either in-theater or elsewhere. Due to changes in
days, the highest threshold for injury (excluding death).
the methodology DOD uses to count the number of
personnel in various stages of deployment and in supporting
Issues for Congress
roles, trends in troop levels since FY2018 may be subject to
Congress faces enduring oversight issues related to current
some variation.
and future war costs, chiefly:
DOD Contractors in CENTCOM
Budgeting for long wars: Historically, Congress has
DOD contractors represent another significant—but often
funded major military operations in stages. At the outset of
overlooked—category of military personnel working in
conflict, Congress has typically provided supplemental
support of contingency operations. In FY2018, an average
appropriations to address the most pressing military needs.
of 48,102 U.S., local, and foreign nationals were employed
In cases where hostilities persisted, war funding was
in CENTCOM’s area of operations. These represent
gradually incorporated into the annual base budgeting
roughly 65% the total number of American military and
process. Congressional funding for OCO/GWOT has
civilian personnel in support of OCO operations in theater
broken this mold with the persistent use of a separate
(74,033).
designation to pay for prolonged military operations.
Congress may wish to consider whether these or some
Figure 2. U.S. Forces Engaged in OCO Operations
alternate models are effective templates for funding future
Compared to Contractors in CENTCOM
military conflicts.
Clarifying base vs. war funding: The use of the OCO
designation for funding both war and non-war requirements
has created ambiguity about enduring costs unrelated to
ongoing conflicts. For greater oversight and to improve
future defense planning, Congress may wish to consider
durable alternatives for discriminating between the
temporary costs of contingency operations and long-term
funding for base budget activities.
Government-wide war costs: No government-wide
reporting consistently accounts for both DOD and non-
Source: Contractor data provided by DOD; Troop levels from
DOD war costs. As a consequence, independent analysts
annual DOD Comptrol er “Defense Budget Request Overview.”
have come to different conclusions about the total amount.
Notes: Excludes military personnel in-CONUS and elsewhere in
Widely varying estimates risk misleading the public and
support of OCO operations.
distracting from congressional priorities. Congress may
U.S. Military Casualties
wish to require future reporting on war costs that
consolidates interagency data (such as health care costs for
Since 9/11, approximately 6,967 U.S. servicemen and
combat veterans or international aid programs) in a
women have died during OCO/GWOT operations. An
standardized, authoritative collection.
additional 52,802 have been wounded.
Approximately 62% (36, 885) of all war-related incidents
Christopher T. Mann, Analyst in Defense Policy and
that resulted in U.S. military casualties have occurred
Trade
during operations in Iraq, including Operation Iraqi
https://crsreports.congress.gov
U.S. War Costs, Casualties, and Personnel Levels Since 9/11
IF11182
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF11182 · VERSION 1 · NEW
April 18, 2019
U.S. War Costs, Casualties, and Personnel Levels Since 9/11
Seventeen years have passed since the U.S. initiated major
In Iraq and Syria, obligations for war fell with the departure
military operations following the September 11, 2001,
of most U.S. troops in December 2011, but rose again as air
terrorist attacks. In the intervening period, operations first
and ground operations against ISIS intensified. Between
classified as Global War on Terror (GWOT) and later
FY2016 and FY2018, the U.S. obligated an average of $7.2
Overseas Contingency Operations (OCO) have varied in
billion annually for operations in Iraq and Syria.
scope. Though primarily focused on locations in
Afghanistan and Iraq, they have also included territories
DOD Non-War Program Costs
throughout Central and Southeastern Asia, the Middle East,
According to DOD reporting, roughly 12% ($.2 trillion) of
and Africa. This In Focus summarizes major expenditures
all funding appropriated through war-related requests since
on U.S. war operations, reconstruction assistance, troop
9/11 has funded non-war programs. These include
levels and casualties, and ongoing issues for Congress. This
congressional transfers to OCO, funding for the European
analysis narrowly defines war/non-war costs as OCO-
Deterrence Initiative, non-DOD classified programs,
designated appropriated funds associated with overseas
adjustments for (non-GWOT) fuel costs, and Army
operations as designated in DOD’s official “Cost of War
modularity programs (service restructuring).
(CoW)” report. Other observers may define war operations
or costs more broadly (see “Issues for Congress” section).
Use of the OCO Designation
Estimates of the cumulative costs of war are complicated by
Department of Defense War Costs
the use of OCO-designated funds for base budget activities.
Congress has appropriated a total of $1.55 trillion in
Under current law, funding designated for emergencies and
discretionary amounts to the Department of Defense (DOD)
overseas contingencies is not counted under budget limits
for war funding since 9/11, according to DOD reporting.
set annually by congressional budget resolutions. After
(See following section for OCO non-war expenditures.)
passage of the Budget Control Act (BCA) in 2011,
Obligations of those amounts peaked during two surges of
exceeding such budget caps triggers across-the-board cuts
U.S. military activity; first in Iraq in FY2008 ($140 billion),
(sequestration) to agency programs.
and then in Afghanistan in FY2011 ($97 billion).
As a means of complying with the BCA, Congress and the
Figure 1. Iraq and Afghanistan: War Spending and
president have increasingly designated substantial amounts
Troop Levels Since 2008
of funding as OCO to provide for base military activities.
Because of this practice, some argue that OCO has become
a slush fund that obscures the true cost of both war and non-
war spending. Others argue that the OCO designation
affords necessary flexibility to apply funds when and where
needed.
Base and Enduring Requirements
DOD’s FY2020 budget request debuts new OCO funding
categories that identify the requirement for which the
portion of OCO is intended. These requirement categories
include the following:
Source: For costs, DOD “Cost of War,” September 2018; for troop
Direct War Requirements ($25.4 billion; 15%):
levels, FY2020 DOD Comptrol er “Defense Budget Request
Direct combat support and partnership training costs.
Overview.”
OCO for Enduring Requirements ($41.3 billion;
As a percentage of total OCO-designated obligations, the
24%): Indirect operational costs likely to remain even
two conflicts have been roughly equivalent. Obligations for
after GWOT combat operations have ended; also funds
operations primarily in Afghanistan represent 49% ($737
European Deterrence Initiative and Ukraine Security
billion) overall, while those for Iraq represent 51% ($759
Assistance.
billion).
OCO for Base Requirements ($97.9 billion; 56%):
Base funding included to comply with BCA spending
Over the past three years, obligations for war spending have
limits.
averaged $47 billion per year, mostly to fund the operating
Emergency Requirements ($9.2 billion; 5%):
support costs of U.S. forces in and around Afghanistan.
Includes $2 billion in disaster relief and $7.2 billion
Between FY2016-FY2018, the Afghan Security Forces
Fund comprised 9.16% of all obligations for Afghanistan.
intended for construction of southwest border wall.
https://crsreports.congress.gov
U.S. War Costs, Casualties, and Personnel Levels Since 9/11
Non-DOD Reconstruction Costs
Freedom, Operation Inherent Resolve, and Operation New
Congress has appropriated $44.8 billion to non-DOD
Dawn. Troops killed or wounded in operations primarily
agencies (and civilians) since 2002, for reconstruction and
associated with Afghanistan—Operation Enduring Freedom
relief operations in Afghanistan. The largest agency
and Operation Freedom’s Sentinel—represent 38%
involved in the effort has been USAID (54%), which
(22,884) of the remainder.
administers a foreign assistance account called the
Economic Support Fund (ESF). The ESF accounts for $20.5
Though most U.S. war casualties since 9/11 have occurred
billion, or roughly 46% of all non-DOD reconstruction
within the territories of Iraq and Afghanistan, 383 U.S.
assistance directed to Afghanistan.
personnel have died during contingency operations
elsewhere, such as at locations in Africa, South Asia,
For Iraqi reconstruction and relief efforts (2003-2012),
Central Asia, Europe, the United States, the Middle East, or
Congress provided multiple funding streams. Roughly $10
at sea.
billion has been allocated to non-DOD agencies, primarily
USAID and the State Department for the Iraq Relief and
Contractor Casualties
Reconstruction Fund (IRRF) and the ESF.
DOD does not systematically record the deaths or injuries
of U.S. contractors. Data compiled by the Department of
U.S. Troop Levels
Labor suggest that 3,413 civilian employees under contract
Approximately 22,200 troops currently serve in
with the U.S. government for public works or national
Afghanistan (15,000), and Iraq and Syria (7,200). An
defense have been killed in Afghanistan and Iraq in the
additional 65,622 American military and civilian personnel
years since 9/11. An additional 38,953 have sustained
operate in support of broader contingency operations; they
work-related injuries that resulted in four or more lost work
are located either in-theater or elsewhere. Due to changes in
days, the highest threshold for injury (excluding death).
the methodology DOD uses to count the number of
personnel in various stages of deployment and in supporting
Issues for Congress
roles, trends in troop levels since FY2018 may be subject to
Congress faces enduring oversight issues related to current
some variation.
and future war costs, chiefly:
DOD Contractors in CENTCOM
Budgeting for long wars: Historically, Congress has
DOD contractors represent another significant—but often
funded major military operations in stages. At the outset of
overlooked—category of military personnel working in
conflict, Congress has typically provided supplemental
support of contingency operations. In FY2018, an average
appropriations to address the most pressing military needs.
of 48,102 U.S., local, and foreign nationals were employed
In cases where hostilities persisted, war funding was
in CENTCOM’s area of operations. These represent
gradually incorporated into the annual base budgeting
roughly 65% the total number of American military and
process. Congressional funding for OCO/GWOT has
civilian personnel in support of OCO operations in theater
broken this mold with the persistent use of a separate
(74,033).
designation to pay for prolonged military operations.
Congress may wish to consider whether these or some
Figure 2. U.S. Forces Engaged in OCO Operations
alternate models are effective templates for funding future
Compared to Contractors in CENTCOM
military conflicts.
Clarifying base vs. war funding: The use of the OCO
designation for funding both war and non-war requirements
has created ambiguity about enduring costs unrelated to
ongoing conflicts. For greater oversight and to improve
future defense planning, Congress may wish to consider
durable alternatives for discriminating between the
temporary costs of contingency operations and long-term
funding for base budget activities.
Government-wide war costs: No government-wide
reporting consistently accounts for both DOD and non-
Source: Contractor data provided by DOD; Troop levels from
DOD war costs. As a consequence, independent analysts
annual DOD Comptrol er “Defense Budget Request Overview.”
have come to different conclusions about the total amount.
Notes: Excludes military personnel in-CONUS and elsewhere in
Widely varying estimates risk misleading the public and
support of OCO operations.
distracting from congressional priorities. Congress may
U.S. Military Casualties
wish to require future reporting on war costs that
consolidates interagency data (such as health care costs for
Since 9/11, approximately 6,967 U.S. servicemen and
combat veterans or international aid programs) in a
women have died during OCO/GWOT operations. An
standardized, authoritative collection.
additional 52,802 have been wounded.
Approximately 62% (36, 885) of all war-related incidents
Christopher T. Mann, Analyst in Defense Policy and
that resulted in U.S. military casualties have occurred
Trade
during operations in Iraq, including Operation Iraqi
https://crsreports.congress.gov
U.S. War Costs, Casualties, and Personnel Levels Since 9/11
IF11182
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF11182 · VERSION 1 · NEW