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December 9, 2020
Defense Primer: Department of Defense Pre-Positioned Materiel
As part of its global posture, the U.S. military maintains
(CCDRs) determine PWRM operational requirements in
war reserve materiel (WRM), stocks of “mission-essential
accordance with strategic guidance; the Joint Staff then
secondary items, principal and end items, and munitions,”
reviews and validates these requirements. The military
to “attain and sustain operational objectives in scenarios”
services maintain and administer PWRM to satisfy
authorized by the Department of Defense (DOD). Some of
validated requirements and meet the needs of CCDRs. The
this materiel, designated pre-positioned WRM, or PWRM,
services routinely rely upon the Defense Logistics Agency
is “strategically located to facilitate a timely response ...
and contractor support to maintain PWRM.
during the initial phase of an operation.” PWRM is stored
worldwide at or near points of planned use in specialized
Several sections within Title 10, United States Code
facilities and dedicated ships.
(U.S.C.) govern PWRM.
Why does DOD pre-position materiel?
10 U.S.C. §2229. Requires the Secretary of Defense to
maintain a strategic policy on pre-positioned materiel
The primary purpose of PWRM is to reduce military
and to certify annually that current PWRM “meet all
response times and ensure timely support of operations in
operations plans, in both fill and readiness.” The
their initial phases until follow-on capabilities are available
FY2014 National Defense Authorization Act (NDAA,
and supply chains are established. PWRM, airlift, and
P.L. 113-66) amended §2229 to require a one-time
sealift comprise the three legs of the strategic mobility triad
submission of DOD’s plan to implement its strategic
that enables military power projection. Each leg of the triad
policy.
has its own inherent strengths and weaknesses in speed,
capacity, cost, and infrastructure requirements. Pre-
10 U.S.C. §2229a. Mandates an annual report to
positioning materiel reduces the demands for strategic
Congress, submitted prior to the submission of the
airlift and sealift assets by locating heavy and bulky
President’s budget request, on the status of pre-
materiel closer to the theater of operations. Unlike airlift,
positioned stocks at the end of the last fiscal year.
PWRM is not constrained by the limited capacity of
10 U.S.C. §229 note. Charges the Secretary of Defense
transport aircraft, but it comes with increased infrastructure
with ensuring that service secretaries have funds to
costs associated with storing and maintaining stocks.
reconstitute pre-positioned stocks in accordance with the
Typically, personnel and a limited amount of equipment are
requirements under the strategy outlined in §2229.
transported into a theater, where they draw and prepare
PWRM to rapidly resource deploying forces.
Sample Funding for PWRM
Two appropriations accounts primarily fund PWRM:
For example, according to the Congressional Budget
Procurement, and Operations and Maintenance (O&M).
Office, during Operation Desert Shield PWRM enabled the
Figure 1 displays requested annual funding levels for pre-
delivery of Marine Corps armored units to the Persian Gulf
positioning in the European Deterrence Initiative (EDI)
one month before the arrival of other armored units shipped
from FY2015 to FY2021. Since FY2017, PWRM has been
from the United States. Similarly, during Operation Iraqi
the largest category of EDI spending. The FY2021 NDAA
Freedom, DOD made extensive use of afloat stocks and
would authorize the requested $282.1 million to support
materiel positioned ashore in the Middle East and Europe to
logistics and prepositioning of equipment as part of the
provide deployed forces essential equipment and supplies.
Pacific Deterrence Initiative.
PWRM can also be used as a signal of U.S. intentions.
Materiel stored overseas can demonstrate commitment to
allies and partners or enhance the deterrence of potential
adversaries. Additionally, units deploying to a theater for
training and exercises may utilize pre-positioned
equipment, which allows these forces to practice
withdrawing and preparing PWRM for operations.
Responsibilities and Management
The Under Secretary of Defense for Acquisition and
Sustainment establishes and maintains a DOD-wide
strategic policy for WRM and PWRM. The military
departments, combatant commands, defense agencies, and
other DOD components are also responsible for issuing
component-specific guidance. Combatant Commanders
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Defense Primer: Department of Defense Pre-Positioned Materiel
Figure 1. EDI Pre-Positioning Funding Requests,
airfield equipment. Each squadron is capable of discharging
FY2015-FY2021
its cargo pierside, ship-to-ship, ship-to-shore, or by air. As
displayed in Figure 2, MPSRON-2 is based in Diego
Garcia, while MPSRON-3 is based in Guam and Saipan.
MCPP-N consists of ground equipment, munitions, and
aviation support equipment stored inside various cave
facilities near Trondheim, Norway. MCPP-N stocks are
sufficient to supply a Marine Expeditionary Brigade with
munitions for 30 days and equip an infantry battalion task
force, combat logistics battalion, and aviation squadron.
Air Force PWRM
The Air Staff’s Director of Logistics is responsible for Air
Source: CRS analysis based on Under Secretary of Defense
Force PWRM policy and planning, while Air Force
Comptrol er information, available at
Materiel Command manages stocks. The Air Force utilizes
https://comptrol er.defense.gov/Budget-Materials/.
munitions stocks positioned at bases around the world and
Selected PWRM Programs
additional materiel located aboard two munitions vessels.
Army Pre-Positioned Stocks (APS)
These vessels belong to MSC and are sometimes under the
tactical control of the MPSRONs. The Air Force also pre-
The Army considers APS materiel “a cornerstone of the
Army’s ab
positions consumables and force generation sets designed
ility to rapidly project power.” It is located
to provide expeditionary airfield, fuel support, damage
around the world in seven stocks. Army Materiel Command
recovery, and medical capabilities.
(AMC) manages APS, while Army Sustainment Command
and other AMC subordinate commands maintain the stocks
Figure 2. Selected PWRM Locations and Contents
through regional Army Field Support Brigades and
Battalions. APS contain several categories of materiel:
Unit Equipment Sets contain combat equipment and
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 Projects (OPROJ) contain equipment to
provide strategic capabilities specific to CCDR
requirements, such as engineering or petroleum
distribution equipment.
Army War Reserve Sustainment Stocks contain
materiel (including vehicles and equipment) to sustain
the fight by replacing combat losses and supplies
consumed during operations.
APS also includes War Reserve Stocks for Allies, 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). These stocks are
excluded from the DOD-wide definition of PWRM.
U.S. Navy and Marine Corps Pre-Positioning
The Navy and Marine Corps rely on the afloat Maritime
Prepositioning Force (MPF) and the ashore Marine Corps
Prepositioning Program-Norway (MCPP-N) to expedite the
Source: Created by CRS. MCPP-N and MPSRON information from
deployment of Marine Air-Ground Task Forces (MAGTFs).
Joint Publication 4-01, The Defense Transportation System (July
The Marines’ Blount Island Command, a subordinate of
2017). APS information from U.S. Army G-4.
Marine Corps Logistics Command, maintains MPF and
Notes: APS-1 is designated for U.S. Army North Homeland Defense
MCPP-N.
missions or for use by overseas Army forces.
The MPF consists of two Maritime Prepositioning Ship
Considerations for Congress
Squadrons (MPSRONs), operated by the Navy’s Military
Alignment with the National Defense Strategy. A
Sealift Command (MSC). Each MPSRON carries unit
potential oversight issue for Congress is whether DOD’s
equipment and 30 days of supply for one brigade-sized
MAGTF when combined with an echelon of personnel,
pre-positioned stocks properly align with the National
Defense Strategy. Congress may wish to review whether
light equipment, and combat aircraft. MPSRONs also
contain additional capabilities such as an expeditionary
it receives sufficient information to adequately assess
medical facility, Naval support element, Naval construction
this alignment. A January 2019 Government
Accountability Office (GAO) report found that “DOD
element, and bridging, aviation support, and expeditionary
continues to provide incomplete information to
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Defense Primer: Department of Defense Pre-Positioned Materiel
Congress on the department’s prepositioned stock
DOD’s annual funding requests for PWRM. Congress
programs,” and “DOD has not fully implemented a joint
faces the competition for funding among pre-positioned
oversight approach for managing prepositioned stock
stocks and other mobility capabilities and resourcing
programs...” (GAO, Prepositioned Stocks: DOD Needs
programs.
Joint Oversight of the Military Services’ Programs,
GAO-19-244, January 2019).
Tyler F. Hacker, Analyst in Defense Logistics
Annual funding. Another potential oversight issue for
IF11699
Congress is whether to approve, reject, or modify
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