Defense Primer: U.S. European Command (EUCOM)

U.S. European Command (USEUCOM, commonly referred to as EUCOM) is one of 11 combatant commands (CCMDs) within the Department of Defense (DOD, which is "using a secondary Department of War designation," under Executive Order 14347 dated September 5, 2025).

EUCOM is responsible for the "command and control of U.S. military forces in Europe." The EUCOM commander, who commands all U.S. forces stationed in Europe, has traditionally had dual-hatted responsibilities (i.e., simultaneously overseen two distinct organizations), also serving as the North Atlantic Treaty Organization's (NATO) Supreme Allied Commander Europe (SACEUR), the alliance's chief military commander.

Since 2014, EUCOM has increasingly focused on deterring Russia and providing assistance to Ukraine. In November 2022, the command established the Security Assistance Group-Ukraine (SAG-U) to support long-term coordination of training and equipping the armed forces of Ukraine.

Background

EUCOM was established in 1947. Since 1950, as a matter of tradition, the North Atlantic Council, the primary decisionmaking body within NATO, has asked the U.S. President to nominate an American officer to serve as SACEUR, though no formal council resolution or treaty requires the council to do so.

Mission and Organization

EUCOM, led by a four-star general or admiral, is headquartered at Patch Barracks in Stuttgart, Germany. The Senate confirmed the current EUCOM commander, U.S. Air Force General Alexus Grynkewich, in June 2025.

According to EUCOM, the command's mission is to "deter conflict, maintain peace and security, and provide strategic depth through military operations, exercises and security cooperation with NATO allies and partners." In April 2025 testimony, then-EUCOM commander General Christopher Cavoli identified three strategic imperatives for EUCOM: "Defend the homeland forward; project U.S. combat power globally; and deter Russian aggression."

Area of Responsibility. The EUCOM area of responsibility (AOR) spans Europe, the Caucasus, Russia, and Iceland, encompassing 50 countries and territories. This AOR changed in 2008, when the newly established U.S. Africa Command (AFRICOM) took responsibility for overseeing U.S. military activities on the African continent; in 2021, when DOD shifted Israel to U.S. Central Command's AOR; and in June 2025, when DOD shifted Greenland to the U.S. Northern Command (NORTHCOM) AOR.

EUCOM's AOR has 30 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; there are also 19 other military sites across EUCOM's AOR that the U.S. military has used or to which it has access (see Figure 1).

Figure 1. EUCOM Military Bases and Selected Sites

Source: CRS analysis of unclassified U.S. government documentation, updated June 17, 2025. For more information about EUCOM and the methodology used to develop this map, see CRS Report R48123, U.S. Overseas Basing: Background and Issues for Congress. Notes: Some dots may reflect more than one base or site. This map may not show all facilities where the United States has an access agreement with host nations within the selected geographic range. Inclusion or exclusion may not reflect current deployments and operations. Names and boundary representations are not necessarily authoritative.

Components. All five DOD armed services, as well as U.S. Special Operations Command (SOCOM), provide forces to EUCOM. According to General Cavoli, as of April 2025, nearly 80,000 servicemembers were assigned within the EUCOM AOR. According to DOD, as of September 2025, the majority of these personnel were stationed in Germany, Italy, and the United Kingdom.

Budget

DOD budget documents do not typically enumerate funding for CCMDs. With certain exceptions, appropriations for CCMDs are largely dedicated to operations and maintenance accounts for headquarters and mission support activities, while joint force personnel and operations at CCMDs are typically funded by individual military services. In supporting the Army secretary's role as combatant command support agent, the Department of the Army provides administrative and logistical support for EUCOM's headquarters. In FY2026, the Army requested $385.7 million for such activities.

In the past, DOD has published a separate budget exhibit for the European Deterrence Initiative (EDI), which identified "specific investments in the base budget that support deterring Russian aggression against NATO" but did not reflect a comprehensive picture of EUCOM's operating costs. Initiated by DOD in FY2015 and required by Congress since December 2019 (P.L. 116-92, §1243), the EDI budget exhibit has displayed funding in various categories, including line of effort, DOD component, appropriation type and account, and line item. DOD has not published an FY2026 EDI budget display. Congress in December 2025 (P.L. 119-60, §1250) created an additional requirement that the EUCOM commander submit an "independent assessment" of activities and resources required for U.S. deterrence and defense posture in Europe.

Issues for Congress

Shifts in Strategic Priorities

In December 2025 and January 2026, respectively, the second Trump Administration published its first National Security Strategy (NSS) and National Defense Strategy (NDS). While the Biden and first Trump Administrations NSSs and NDSs identified Russian aggression as a threat to European allies and the United States, these new strategy documents largely omit discussion of Russian aggression and call for the United States to enable Europe to take "primary responsibility for its own defense." EUCOM structure and activities may evolve as U.S. strategic priorities shift, to include the issues detailed below. Congress may act to support, reject, or modify implementation of this strategy through legislation (including appropriations) and oversight.

EUCOM Force Posture

In April 2025, DOD officials reportedly were considering, as part of a broader assessment of U.S. military posture, a plan to withdraw 10,000 of the 20,000 troops deployed to Eastern Europe by the Biden Administration in 2022 as part of an effort to strengthen the defenses of countries bordering Ukraine. In his April 2025 testimony to the House Armed Services Committee (HASC), General Cavoli highlighted that the current troop levels in EUCOM represent a reduction "from the 105,000 service members postured in Europe after Russia invaded Ukraine in 2022" and were approximately "20% of the U.S. forces that were stationed in Europe during the Cold War to deter the Soviet Union." In October 2025, DOD informed some U.S. allies of a decision to withdraw some U.S. troops from Eastern Europe. Some Members of Congress have expressed concern regarding such proposed force reductions, citing Russia's military buildup and ongoing war in Ukraine.

Congress could consider such proposed force structure changes, their funding, and implications for national security, as it continues to monitor threats to the United States and its allies from Russia. In December 2025, Congress limited DOD funding for reduction of troops in the EUCOM AOR, divestment from EUCOM sites and property, or the U.S. relinquishment of the EUCOM Commander/SACEUR role absent certain DOD certification to Congress (P.L. 119-60, §1249). Congress also established the Baltic Security Initiative "for the purpose of deepening security cooperation" with Baltic state militaries (P.L. 119-60, §1247).

EUCOM-NATO SACEUR Role

Some Members of Congress raised concerns over March 2025 press reports about DOD proposals to restructure the leadership role of the EUCOM commander, including relinquishing the position of SACEUR, without coordination with Congress. General Cavoli stated in April 2025 testimony that such a change would affect the employment planning for U.S. nuclear weapons in Europe intended for extended deterrence of NATO. As stated above, Congress has limited DOD funding for a U.S. relinquishment of the EUCOM Commander/SACEUR role Congress (P.L. 119-60, §1249).

Potential CCMD Restructuring

In February 2025, Trump Administration officials reportedly indicated they were examining restructuring some CCMDs, including potentially merging EUCOM and AFRICOM. Congress in December 2025 limited DOD funding for geographic combatant command consolidation (P.L. 119-60, §916).

In June 2025, DOD announced that President Donald J. Trump "ordered a change to the Unified Command Plan" (a classified executive branch document that articulates CCMD responsibilities) that shifted Greenland from EUCOM to NORTHCOM's AOR. Some analysts have stated that such a move could enable the United States to expand its Golden Dome missile defense initiative, while others have expressed concern that it may increase tensions with European allies.

Under 10 U.S.C. §161, Congress has delegated to DOD the authority to alter, adjust, create or disestablish CCMD structures, missions, and AORs. Congress retains the authority to direct or prohibit such realignments. Congress may consider the feasibility, efficiency, risks, and costs of modifying AORs, consolidating commands, alternative command structures, and how such changes may affect U.S. national security interests.