Defense Primer: U.S. Southern Command (SOUTHCOM)

Defense Primer: U.S. Southern Command (SOUTHCOM)

Defense Primer: U.S. Southern Command (SOUTHCOM)

July 21, 2025 (IF13067)

U.S. Southern Command (USSOUTHCOM, commonly referred to as SOUTHCOM) is the Department of Defense (DOD) unified combatant command (CCMD) responsible for command and control of U.S. military forces, contingency planning, and security cooperation across the Caribbean, Central America, and South America (see Figure 1). According to 10 U.S.C. §161, a unified combatant command is "a military command which has broad, continuing missions and which is composed of forces from two or more military departments."

Background

SOUTHCOM traces its origins to "U.S. military units dispatched to Panama in the early 20th Century." According to the command, it became a unified military headquarters "during World War II when U.S. planners established the U.S. Caribbean Defense Command." In the 1950s, the command's focus shifted from the Caribbean to Central and South America. In 1963, the Caribbean Defense Command was formally renamed U.S. Southern Command.

SOUTHCOM works with foreign militaries to "counter threats from transnational criminal organizations, violent extremist organizations, and malign regional and external state actors." To train, equip, and professionalize partner militaries, the command uses various types of funding and authorities, such as international military education and training and foreign military financing. SOUTHCOM conducts multinational training exercises, facilitates combined operations, and engages in DOD security cooperation activities, such as DOD's State Partnership Program with the National Guard, humanitarian assistance and disaster relief, and "train and equip" efforts under 10 U.S.C. §333.

Mission and Organization

According to SOUTHCOM, its mission "deters aggression, defeats threats, rapidly responds to crises, and builds regional capacity, working with our allies, partner nations, and U.S. government (USG) team members to enhance security and defend the U.S. homeland and our national interests."

SOUTHCOM's responsibilities include providing force protection for U.S. military resources across its area of responsibility (AOR) and ensuring the defense of the Panama Canal (see Figure 1). SOUTHCOM's AOR has two overseas bases that DOD has consistently used for at least 15 years and at which the U.S. military exercises some degree of operational control: Naval Station Guantanamo Bay in Cuba and Soto Cano Air Base in Honduras. (For more information, see CRS Report R48123, U.S. Overseas Basing: Background and Issues for Congress.) There also are two cooperative security locations (CSLs) in the SOUTHCOM AOR. The Central American CSL is located at the Comalapa International Airport in El Salvador. The Caribbean CSL is located at the Reina Beatrix International Airport in Aruba and the Hato International Airport in Curaçao.

SOUTHCOM is headquartered in Doral, FL, and led by a four-star general or admiral. The current SOUTHCOM commander is U.S. Navy Admiral Alvin Holsey.

Figure 1. SOUTHCOM Area of Responsibility (AOR)

Source: Map created by CRS using data from U.S. Department of Defense and Esri, updated July 14, 2025.

Notes: This map does not show all facilities where the United States may have an access agreement with host nations within the selected geographic range. Inclusion or exclusion does not reflect current deployments and operations. Names and boundary representations are not necessarily authoritative. Executive Order 14172 of January 20, 2025, "Restoring Names That Honor American Greatness," 90 Federal Register 8629, January 31, 2025, changed the name of the Gulf of Mexico to the Gulf of America.

Components

SOUTHCOM comprises four service component commands, one subordinate unified command, and three joint task forces (JTFs). JTF-Bravo supports "humanitarian and civic assistance, counterdrug, contingency and disaster relief operations in Central America." JTF-Guantanamo supports intelligence collection efforts, as well as activities related to the "legal care and custody ... of armed conflict detainees." Joint Interagency Task Force-South (JIATF-South) supports counterdrug operations and efforts to combat transnational crime. Approximately 1,200 active-duty servicemembers and civilian personnel are assigned to SOUTHCOM.

Budget

DOD budget documents do not fully enumerate funding for CCMDs. Forces and operations assigned to CCMDs typically are funded by individual military services, with CCMD funding largely limited to operations and maintenance accounts for headquarters and mission support activities. The military departments serve as combatant command support agents (CCSAs), assisting assigned CCMDs with logistical support via their annual budget requests. The Department of the Army serves as the CCSA for SOUTHCOM headquarters operations. For FY2026, the Department of the Army requested $225.0 million for SOUTHCOM, a decrease from the $257.4 million enacted in FY2025. For FY2026, DOD requested $350.1 million for SOUTHCOM counterdrug programs as part of a broader line item for Drug Interdiction and Counterdrug Activities. SOUTHCOM reportedly identified to Congress a total of $60.2 million in unfunded priorities for FY2026, including $35.0 million for a "Ship Special Mission," which Admiral Holsey has described as "a significant asset in the fight against [transnational criminal organizations]" that helps "keep illicit drugs far from our shores." Section 20011 of the 2025 reconciliation law (P.L. 119-21) appropriated $1 billion for "improving [DOD] border support and counter-drug missions," though it is unclear how that money may be allocated within DOD.

SOUTHCOM's Primary Challenges

According to Admiral Holsey's February 2025 posture statement, SOUTHCOM's primary challenges include

"strategic competition with the People's Republic of China" (PRC, or China) throughout its AOR;

Russian support for "authoritarian regimes in Cuba, Nicaragua, and Venezuela";

transnational crime and regional destabilization;

Iranian efforts to build relationships with authoritarian regimes and develop criminal networks; and

"regional humanitarian crises."

Potential Issues for Congress

Potential CCMD Restructuring

The authority of Congress to shape the structures and organization of CCMDs flows from Article 1, Section 8, clauses 12 through 14, of the U.S. Constitution, which enumerates Congress's power to "raise and support Armies," "provide and maintain a Navy," and "make Rules for the Government and Regulation of the land and naval Forces." Under 10 U.S.C. §161, Congress delegated to DOD the authority to alter, adjust, create, or disestablish CCMD structures, missions, and geographic AORs. Congress retains the authority to direct or prohibit such realignments. The statute requires that "except during time of hostilities or imminent threat of hostilities, the President shall notify Congress not more than 60 days after- (A) establishing a new combatant command; or (B) significantly revising the missions, responsibilities, or force structure of an existing combatant command."

In February 2025, Trump Administration officials reportedly were examining restructuring some CCMDs, including potentially merging SOUTHCOM with U.S. Northern Command (NORTHCOM) to create a command responsible for aerospace and maritime activities for all of North, Central, and South America and the Caribbean (described in news articles as "AMERICOM").

Congress may consider whether or not to modify AORs, consolidate commands, or alter command structures and how such changes may affect U.S. national security interests, along with the feasibility, efficiency, risks, and costs of such potential actions.

SOUTHCOM's Role in Strategic Competition

In the 2025 posture statement, Admiral Holsey assessed that "the actions of nations such as China and Russia" are the most concerning threats in SOUTHCOM's AOR. SOUTHCOM leaders have voiced similar concerns, including that PRC investments in the region's critical infrastructure might increase PRC surveillance capabilities (e.g., space facilities, telecommunications technology) or serve a dual civilian-military purpose (e.g., strategically located ports, including those around the Panama Canal). Admiral Holsey also has warned about Russia's efforts to support authoritarian regimes and spread disinformation in the region. Congress may assess how SOUTHCOM funding, basing, and programming contributes to broader U.S. efforts to counter PRC and Russian influence and whether or not any changes are needed, given shifts in U.S. trade and foreign assistance policies in 2025 during the Trump Administration.

Resources for SOUTHCOM

Admiral Holsey has stated that JIATF-South suspected that more than 3,200 maritime narcotics shipments were bound for the United States in 2024 "but was only able to act" on 9% of such shipments because of declining resources for counterdrug missions. Congress may assess whether or not resources are adequately allocated to SOUTHCOM, including for counterdrug efforts. Congress also may consider whether or not SOUTHCOM needs additional DOD support amid the Trump Administration's pause of nearly all U.S. foreign assistance and subsequent termination of many awards. Some terminated awards may have aligned with SOUTHCOM priorities, and the halt to related activities may have disrupted ongoing efforts. Congress also may assess the potential implications of a possible greater DOD role in regional counterdrug initiatives and other efforts.

CRS Products:

CRS In Focus IF12876, Western Hemisphere: Issues for the 119th Congress

CRS In Focus IF13044, Defense Primer: U.S. Northern Command (USNORTHCOM)

CRS Report R42077, The Unified Command Plan and Combatant Commands: Background and Issues for Congress

CRS Report R48123, U.S. Overseas Basing: Background and Issues for Congress

Note: For questions on combatant commands, contact Hannah D. Dennis. For questions on Latin America and the Caribbean, contact Joshua Klein. Acknowledgments: Robert Switzer, a former National Defense Fellow with CRS, coauthored this product.