US Defense Assets in the Western Pacific

Some of the US’ most high-profile and valuable military and security assets in the Western Pacific are hosted by Pacific Island Countries (PICs).  This blog post will provide an overview of key US security assets in Oceania, their functions, and strategic value. As climate change becomes an increasingly influential factor in military and security initiatives, these assets will be exposed to greater environmental and political risks.

In particular, the Marshall Islands, Palau, and Guam PICs host many strategic US assets. Above all, US Integrated Air and Missile Defense systems (IAMD) designed to protect the US from missile attacks and the freedom to test new technology, heavily depend on basing in Oceania and the Western Pacific. IAMD not only contributes to the strategic stability and the deterrence relationship between the US and China, but also defends against North Korean capabilities and offers security assurances to other Pacific partners such as South Korea and Japan. These objectives feature prominently in the US’ National Security Strategy, Nuclear Posture Review, and its Missile Defense Strategy; US military and security assets in the Western Pacific are foundational capabilities for the Trump administration’s geopolitical goals.

Climate risks – increased frequency of extreme weather events, rising sea levels, higher ambient temperatures, among others – will create challenges for maintaining US assets and capabilities. These same risks will also impact the local and national politics of each PIC. Climate risks therefore impact not only US assets, but also the political basis for which those assets can be employed.

Below is an overview of key US national and international security assets in the Marshall Islands, Palau, and Guam.

Marshall Islands:

  • Ronald Reagan Ballistic Missile Defense Test Site – Offers a testing facility for radars, missiles, and satellites that include Raytheon, NASA, General Dynamics, MIT Lincoln Labs, and the Missile Defense Agency (MDA), among others. Current notable capabilities tested at the Reagan Test Site include Aegis, Terminal High-Altitude Air Defense, and Patriot systems.
  • Space Fence Facility – US Air Force advanced surveillance system for tracking satellites and space debris in order to enable proactive space situational awareness and force modernization. This is also part of broader US efforts to enhance its space navigation capabilities in an increasingly crowded and contested orbital environment.


  • Air and Maritime Domain Awareness (ADA/MDA) radar – In August 2017 the US and Palau announced in a joint statement plans to build Air and Maritime Domain Awareness (ADA/MDA) radar. The equipment is intended to monitor air and maritime traffic in the vicinity of Palau to enhance Palau’s enforcement of its territorial waters and exclusive economic zones, in addition to enhancing tracking capabilities in both domains for defense and security purposes.
  • Tactical Mobile Over the Horizon Radar (TACMOR) – Separate from the ADA/MDA systems is the Talon TACMOR intended to generate greater air domain awareness for the US Air Force, in addition to capabilities that can be shared with Palau.


  • Terminal High Altitude Air Defense (THAAD) Battery – includes launchers for hit-to-kill missile interceptors, operations center, and AN/TPY-2 radar. Not only does this system primarily defend against potential North Korean launches, it also interoperates with Aegis missile defense systems operated by the Navy at sea.
  • Joint Region Marianas – is a US Navy-controlled joint base combining Naval Base Guam and Andersen Air Force Base. It allows the Navy freedom of action throughout the Pacific, especially for its fast-attack nuclear submarines. The airbase also enables US bomber and transport aircraft access to the wider Pacific. Both of these installations manage their respective and joint space operations

The above facilities are essential to US Indo-Pacific Command (USINDOPACOM) operations, in addition to other US defense activities. Of particular note is the prevalence of missile, ballistic missile defense, radar, and space capabilities and how dependent US capabilities are on these facilities’ basing in the region. Simply put, the US would not be able to test new technology to counter and defend against emerging threats, nor would it be able to project the force it currently does without the PICs. And the capabilities tested here are employed in theaters and COCOMs across the globe. The US therefore needs to maintain these assets if it wishes to address new areas and periods of competition, and while it has agreements currently in effect that allow US basing and power projection, these cannot be taken for granted.

Rising sea levels, nuclear waste management issues, and increased extreme weather events demonstrate that this region is particularly prone to environmental risks. Missile test sites cannot function when they are underwater, and radar systems need intact antennae to function – rising levels and increased storm severity will increasingly threaten the survivability of such assets, in addition to the livelihoods and security of local citizens.

The current COFAs expire in 2023 and 2024, and Guam is pushing for a plebiscite on its own COFA status. These developments come at a time where China is trying to make its own inroads into the region, and as these states face the threat of climate change. Renewing the COFAs and guaranteeing US access to its facilities will require a more robust and comprehensive approach than in the past; not only will it need to divert more resources to adapt to climate change and its associated risks but also make greater contributions to state governance capacities to do the same. Public opinion in PIC and COFA states matters as they factor significantly in local and national politics. Public grievances regarding the US military presence and climate concerns, in addition to other needs will inform the negotiating positions for the PICs in their upcoming COFA renewals. US commitments to investments in their resiliency and disaster preparedness will likely improve the US-COFA States relations, enabling US power projection in the next COFA framework

If the US wishes to sustain its operational and experimental IAMD capabilities, it will need to make substantial steps towards acknowledging the daily impacts of – and adapting to – climate change, investing in disaster risk reduction (not only in terms of USINDOPACOM capabilities but also in local contexts) and consider making significant commitments to enhancing PIC governance capacity. PICs are strategic partners for the US whose utility for regional security will only increase.

The views expressed in this article are strictly those of the author and do not necessarily represent the views of the U.S. Air Force, the U.S. Department of Defense, or the U.S. Government. All information contained above was accessed from online unclassified open-source publications.

Jonah Bhide is a second year global policy studies masters candidate at the LBJ School where he studies the intersection of US national security and foreign policy. He interned with the US Military Delegation to NATO HQ in Brussels, Belgium in the summer of 2019. Jonah graduated from the US Air Force Academy in May 2018 with a BS in Political Science, and will attend pilot training upon completing his master's program.

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