Updated December 23, 2022
Defense Primer: Department of Defense Pre-Positioned Materiel
As part of its global posture, the Department of Defense
Several sections of Title 10, U.S Code (U.S.C.) govern
(DOD) maintains stocks of mission-essential equipment,
PWRM, including the following:
supplies, and munitions deemed sufficient to attain and
10 U.S.C. §2229. Requires the Secretary of Defense to
sustain strategic objectives in contingency plans. To
maintain a strategic policy on pre-positioned materiel
facilitate rapid deployment of U.S. forces during the initial
and to certify annually that current PWRM “meet all
phases of operations, some of this materiel is pre-positioned
operations plans, in both fill and readiness.”
at or near points of planned use in specialized facilities (i.e.,
10 U.S.C. §2390. Authorizes sale of PWRM to non-
ashore) and dedicated ships (i.e., afloat).
DOD entities during declared international crisis.
Why does DOD pre-position materiel?
Requires prompt replenishment of stocks.
10 U.S.C. §118b. The FY2021 National Defense
Pre-positioned war reserve materiel (PWRM) reduces
Authorization Act, as amended, requires DOD to submit
demand for strategic airlift and sealift assets by locating
a classified report to Congress following publication of
heavy and bulky materiel closer to the theater of operations.
a new National Defense Strategy detailing PWRM
It sustains warfighters while supply lines are established
requirements 5, 10, and 25 years into the future.
and the industrial base surges production. PWRM may also
be used to signal U.S. intentions. Materiel stored overseas
Funding
may demonstrate commitment to allies and partners or
enhance the deterrence of potential adversaries. As stated in
As with many other military functions for which DOD is
the Army Operations Field Manual (FM 3-0), a robust
both a customer and key supplier, successful management
PWRM inventory is essential to providing credible support
of DOD pre-positioned materiel involves both appropriated
to partner forces during a crisis. Accordingly, enhanced pre-
funds from Congress and defense working capital funds that
positioning of equipment, munitions, fuel, and materiel is a
purchase and manage inventories to stabilize item supplies
core focus of both the European Deterrence Initiative (EDI)
and prices.
and Pacific Deterrence Initiative (PDI). During Operation
Two defense appropriations primarily fund PWRM:
Desert Shield in 1990-1991, PWRM enabled the delivery of
Operations and Maintenance (O&M) and Procurement.
Marine Corps armored units to the Persian Gulf one month
Services use O&M funds for both the pre-positioned
before the arrival of other armored units shipped from the
materiel itself and the necessary expenses required to
United States, according to the Congressional Budget
operate humidity-controlled ashore facilities and ships
Office. In 2003 during Operation Iraqi Freedom, DOD
carrying afloat assets throughout the year. O&M PWRM
made extensive use of PWRM stored in the Middle East
requirements are categorized as either mobilization or
and Europe. Most recently, in 2022 DOD PWRM equipped
operating forces requirements in DOD budget justifications.
U.S. forces supporting the NATO Response Force
Procurement budgets integrate PWRM requirements within
following Russia’s invasion of Ukraine.
agency-wide requirements for a given weapon system. For
The effectiveness of large PWRM stocks, however, also
example, upgrades to a combat vehicle may include
procurements sufficient for “one Army Prepositioned Stock
makes them potential priority targets for adversary long-
[APS] brigade” along with 4 (non
range weapons in conflict scenarios. Responding to such
-PWRM) Armor Brigade
challenges, DOD’s Joint Concept for Logistics envisions a
Combat Teams.
“comprehensive array” of large and small PWRM stocks
The European Deterrence Initiative (EDI) and Pacific
that can be selectively accessed and quickly shifted between
Deterrence Initiative (PDI) budget exhibits summarize
theaters of operations, even in contested environments.
relevant DOD PWRM activities. For FY2023, EDI’s
Responsibilities and Management
enhanced prepositioning line of effort requests over $687
million for O&M and $586 million for Procurement.
The Under Secretary of Defense for Acquisition and
Selected PWRM Programs
Sustainment establishes and maintains a DOD-wide
strategic policy for WRM and PWRM. Combatant
Army Pre-Positioned Stocks (APS)
Commanders (CCDRs) determine PWRM operational
The Army considers APS materiel “a cornerstone of the
requirements in accordance with strategic guidance; the
Army’s ability to rapidly project power.” Army Materiel
Joint Staff then reviews and validates these requirements.
Each military service (hereafter “service”)
Command (AMC) manages APS, while Army Sustainment
maintains and
Command and other AMC subordinate commands maintain
administers PWRM to satisfy such requirements and meet
the stocks through regional Army Field Support Brigades
the needs of CCDRs. The services rely upon the Defense
and Battalions (See Figure 1). APS contain several
Logistics Agency and contractor support to maintain
categories of materiel:
PWRM, but may seek host nation support for some items.
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Defense Primer: Department of Defense Pre-Positioned Materiel
Unit Equipment Sets contain combat equipment and
Figure 1. Selected PWRM Locations and Contents
supplies to support the Army’s force projection strategy.
Unit sets mirror Army force structure unit equipment
(i.e., brigade combat team or sustainment brigade
equipment sets).
Operational Project Stocks (OPROJ) contain
equipment above normal allowances to provide strategic
capabilities essential to the Army’s strategic deployment
strategy.
Army War Reserve Sustainment Stocks contain
materiel (including vehicles and equipment) to sustain
military operations by replacing combat losses and
consumed supplies.
APS also includes War Reserve Stocks for Allies (WRSA)
—which are stocks owned and funded by the United States
to be released to supported allied forces under the Foreign
Assistance Act (22 U.S.C. §2331h). DOD calculates WRSA
requirements alongside PWRM requirements in joint
scenario planning.
U.S. Navy and Marine Corps Pre-Positioning
The Navy and Marine Corps rely on the afloat Maritime
Prepositioning Force (MPF) and ashore Marine Corps
Prepositioning Program-Norway (MCPP-N) to expedite
deployment of Marine Air-Ground Task Forces (MAGTFs).
The Marines’ Blount Island Command, a subordinate of
Marine Corps Logistics Command, maintains the MPF and
MCPP-N.
The MPF consists of two Maritime Prepositioning Ship
Squadrons (MPSRONs), operated by the Navy’s Military
Sealift Command (MSC). Each MPSRON carries unit
equipment and 30 days of supply for one brigade-sized
Source: Created by CRS. MCPP-N and MPSRON information from
MAGTF when combined with an echelon of personnel,
Joint Publication 4-01, The Defense Transportation System (July
light equipment, and combat aircraft. Each squadron is
2017). APS and USAF PWRM information from U.S. Army G-4 and
capable of discharging its cargo pierside, ship-to-ship, ship-
U.S. Air Force A-4 respectively.
to-shore, or by air. MCPP-N consists of ground equipment,
munitions, and aviation support equipment to supply a
Considerations for Congress
Marine Expeditionary Brigade for 30 days.
PWRM for distributed operations. Recent changes to
service operational concepts and battle doctrine
Key U.S. Air Force PWRM
emphasize the need to sustain military operations across
The Air Force’s PWRM is managed by Air Force Materiel
wider geographical areas than in previous decades. As a
Command. Across 23 worldwide locations, Air Force
result, CCDRs may require more widely distributed and
PWRM stocks consist of dispersed ashore assets and
resilient networks of PWRM assets, both ashore and
munitions necessary to initiate expeditionary operations.
afloat. Congress may wish to evaluate DOD
Some afloat munitions stocks are also stored aboard two
assessments of long-term PWRM requirements, such as
MSC vessels that are under the tactical control of the
those associated with the National Defense Sustainment
relevant geographic CCDR. The Air Force also pre-
and Logistics Review (Title 10 U.S.C. §118b).
positions consumable items such as food and fuel, and sets
Improved Oversight of PWRM. In FY2023, the DOD
of equipment designed to provide expeditionary operational
Office of the Inspector General (OIG) is reportedly
support, fuel support, damage recovery, force protection,
auditing Army PWRM issued in response to Ukraine
and medical capabilities. Air Force PWRM consists of three
and NATO defense forces, along with accountability
major categories of materiel:
controls over transported equipment. Congress may
Common Support Equipment (CSE) sets provide
wish to review whether it receives sufficient information
aerospace ground equipment, vehicles, and munitions
to assess DOD’s pre-positioned stock levels and
support equipment to support initial combat operations.
replenishment rates in light of total requirements for
Fuels Support Equipment (FSE) sets provide ground
strategic and contingency plans.
and aircraft fuels support.
Cameron M. Keys, Analyst in Defense Logistics and
Basic Expeditionary Airfield Resources (BEAR) sets
Resource Management Policy
provide personnel support, infrastructure, and flight line
support at forward operating sites.
IF11699
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Defense Primer: Department of Defense Pre-Positioned Materiel
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