Defense Primer: U.S. Indo-Pacific Command (INDOPACOM)
U.S. Indo-Pacific Command (USINDOPACOM, commonly referred to as INDOPACOM) is one of 11 unified combatant commands in the Department of Defense (DOD, which is "using a secondary Department of War designation," under Executive Order 14347, dated September 5, 2025). The commander of INDOPACOM exercises authority over military forces assigned to the command's area of responsibility (AOR), which includes the Pacific Ocean and about half of the Indian Ocean, as well as countries along their coastlines. Approximately 375,000 military and civilian personnel are assigned to its AOR. Congress may consider whether DOD's budget, posture, and regional strategy supports U.S. national security interests in the Indo-Pacific.
Mission and Organization
The 2026 National Defense Strategy (NDS) directs DOD to maintain a favorable balance of military power in the Indo-Pacific, ensuring "that neither China nor anyone else can dominate us or our allies." The document directs DOD to do so "through strength, not confrontation," by expanding military-to-military communications with China, erecting "a strong denial defense along the First Island Chain," and encouraging "regional allies and partners to do more for our collective defense."
As of September 2025, most of the active-duty U.S. servicemembers assigned to locations in the INDOPACOM AOR were based in Japan (53,490), Hawaii (45,528), South Korea (23,642), and Guam (6,986). DOD operates or has access to over 40 military sites in the region. U.S. forces based at these sites comprise ground units (including the Army's 2nd Infantry Division and the Marine Corps' III Marine Expeditionary Force), naval warships (including an aircraft carrier, destroyers, cruisers, and amphibious assault ships), and aircraft (including rotary-wing, fighter, electronic attack, bomber, airlift, and tanker units).
INDOPACOM is headquartered outside of Honolulu, Hawaii, and commanded by a four-star general or flag officer. To date, all commanders have been Navy admirals; the current commander is Admiral Samuel Paparo. INDOPACOM encompasses five subordinate service component commands (U.S. Army Pacific, U.S. Pacific Fleet, U.S. Marine Forces Pacific, U.S. Pacific Air Forces, and U.S. Space Forces Indo-Pacific) and three subordinate unified commands (U.S. Forces Japan, U.S. Forces Korea, and Special Operations Command Pacific). INDOPACOM routinely participates in multinational exercises and other security cooperation activities with regional partners.
Focal Points in the INDOPACOM AOR
INDOPACOM plans for contingencies throughout the AOR. The following hotspots could for various reasons implicate U.S. national security and military forces.
Taiwan. The People's Republic of China (PRC) claims sovereignty over self-ruled Taiwan and has long vowed to unify with it, by force if necessary. The 1979 Taiwan Relations Act (TRA; P.L. 96-8; 22 U.S.C. §3301) states that it is U.S. policy "to maintain the capacity" to "resist any resort to force or other forms of coercion that would jeopardize" Taiwan's security. The TRA does not require the United States to use force to defend Taiwan, but DOD officials have referred to a conflict in the Taiwan Strait as "the pacing scenario" for which DOD is preparing. As such, DOD has taken steps toward "modernizing [its] capabilities, updating U.S. force posture, and developing new operational concepts," in addition to maintaining long-standing efforts to bolster Taiwan's defensive capabilities.
Korean Peninsula. Perceived threats from North Korea traditionally have served as the raison d'être for the U.S.-South Korea alliance since 1953, when the two countries signed a Mutual Defense Treaty at the end of the Korean War. As North Korea advances its ballistic missile and nuclear weapons programs, the United States faces a number of challenges: enhancing alliance preparedness without triggering a military conflict, reinforcing the credibility of U.S. extended deterrence (or "nuclear umbrella"), and preparing for the eventual transfer of wartime operational control of alliance forces from a U.S. commander to a South Korean commander. Some analysts have suggested that North Korea—with improving military capabilities and seemingly closer relations with Russia and China—may seek to engage in military provocations against United States or South Korea.
South China Sea. Multiple Asian governments claim sovereignty over islands and other geographic features in the South China Sea, one of the world's most heavily trafficked waterways. The PRC, which claims most of the sea, has conducted land reclamation (island-building), constructed military facilities on natural and artificial features, and used coercive tactics to impede the activities of other countries, including the Philippines, a U.S. mutual defense treaty ally. Successive U.S. Administrations have accused the PRC of deploying its military vessels and aircraft in an unsafe and unprofessional manner against U.S. and other militaries operating in the South China Sea.
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Figure 1. The U.S. INDOPACOM AOR and Selected U.S. Bases |
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Source: CRS Report R47589, U.S. Defense Infrastructure in the Indo-Pacific: Background and Issues for Congress. Notes: AFB is Air Force Base; AOR is Area of Responsibility; INDOPACOM is U.S. Indo-Pacific Command; JB is Joint Base; MCAS is Marine Corps Air Station; MCB is Marine Corps Base; NB is Naval Base; and USAG is U.S. Army Garrison. |
East China Sea. The PRC, Japan, and Taiwan all claim sovereignty over the Senkaku Islands in the East China Sea. Since 2010, PRC-Japan tensions over the Senkakus have simmered as PRC maritime forces have increased patrols near the islands, which Japan administers. It has been U.S. policy since 1972 that the Senkakus are covered under Article 5 of the U.S.-Japan Security Treaty, which states that the United States commits to "meet the common danger" of an armed attack on "the territories under the Administration of Japan." Okinawa, which is part of the same island chain, hosts more than half of all U.S. troops based in Japan.
Issues for Congress
Resourcing INDOPACOM. Congress may assess whether DOD funding requests align with national interests and the congressionally mandated NDS. DOD requested $10.0 billion for the Pacific Deterrence Initiative (PDI) in its FY2026 budget. PDI does not represent the totality of departmental resources for INDOPACOM operations in pursuit of regional strategic objectives. Congress may assess the strategic alignment of INDOPACOM funding more holistically, to include basing, personnel, and equipment needs alongside common services and support provided by defense agencies and field activities.
Shifts in Strategic Priorities. U.S. Administrations since the mid-2010s increasingly came to identify competition with the PRC as the organizing principle of the U.S. military's Indo-Pacific posture. Since then, the U.S. military has increased the number of personnel stationed in the region, secured access to new bases (especially in Australia and the Philippines), and developed new operational concepts that emphasize wider and more diversified combat and logistical operations.
The second Trump Administration, however, has placed an increased emphasis on the Western Hemisphere. Whereas the Biden and first Trump Administrations referred to the Indo-Pacific as a "priority theater" and China as the "pacing challenge," the unclassified 2026 NDS does not. Shifts in how U.S. foreign policy prioritizes different regions of the world, such as those shifts that may be directed by the 2026 NDS, could lead to changes in the INDOPACOM AOR. Such changes could include the locations and number of U.S. forces and facilities, as well as the status of the alliances and partnerships that support U.S. basing and overflight, defense production, and integrated training. These changes could affect the types and quantities of weapons and equipment the U.S. military develops and acquires. Congress may support, reject, or modify such changes—for example, by requiring DOD to assign certain numbers of forces and capabilities to the region.
Force Protection. Much of the INDOPACOM AOR is within range of PRC conventional ballistic and cruise missiles, and some locations are vulnerable to North Korean and Russian missiles as well. As a result, U.S. bases, personnel, and weapons systems may be at risk of attack in the event of a regional conflict. Congress may assess the degree to which INDOPACOM's existing air and missile defense architecture affords protection from these threats, and consider whether or not to make additional appropriations, enact legislation, or conduct oversight activities aimed at strengthening these capabilities.