Deterring Russia
U.S. Military Posture in Europe
Seth G. Jones and Seamus P. Daniels | 2025.01.27
Russia’s continuing conventional war in Ukraine, increase in sabotage and subversive activities in Europe, and threats of nuclear escalation pose a serious and long-term challenge to U.S., European, and international security.
Introduction
Russia’s February 2022 invasion of Ukraine, and the ongoing war that has followed, have dramatically shifted the strategic landscape in Europe, triggering the most devastating war on the continent since World War II. More Russian soldiers have died in Ukraine than in all previous Soviet and Russian wars since World War II combined, including Russia’s bloody wars in Afghanistan and Chechnya. The Ukraine war has caused the most significant refugee crisis in Europe since World War II, driving over 6 million Ukrainian refugees to Poland, Germany, the Czech Republic, and other countries. The war has also had substantial humanitarian implications, causing widespread civilian deaths and destruction in Ukraine and disrupting public access to water, electricity, heating, health care, and education.
Despite Russian aggression in Ukraine and increase in gray zone activity across Europe, there has been a robust debate about whether the United States should focus its defense priorities and military posture on the Indo-Pacific to counter China. While the Indo-Pacific is a strategically important region, the United States needs to be prepared to deter two major theater wars—one in Europe and the other in the Indo-Pacific—as well as ensure readiness for contingencies elsewhere, such as in the Middle East and Korean Peninsula. After all, Russia has invaded one country (Ukraine) and waged war in several others, such as Syria. China has not—at least not yet. In its approach to defense planning, the Trump administration should ensure that the allocation of limited forces between the two theaters is tailored to match the unique demands of each region while carefully managing risks and trade-offs.
In examining U.S. posture in Europe, this analysis asks three main questions. What are the main security threats in Europe for the United States and its allies? What are U.S. interests in Europe? What is the appropriate U.S. force posture in Europe? In answering these questions, this analysis comes to several broad conclusions.
First, the United States needs a long-term military presence in Europe focused on NATO’s eastern flank to deter Russian aggression. But the United States should reduce its military footprint in Europe from today’s 5+2 posture to a 4+2 posture with four brigade combat teams (BCTs) and two regional headquarters. Even if there is a successful ceasefire in Ukraine, Russia will likely remain a serious threat to the United States and Europe over the next several years. Russian president Vladimir Putin retains the political will and intentions to expand Russian power abroad, and Russia is reconstituting its military capabilities with help from China, Iran, and North Korea. While the United States may adjust its current posture in Europe, which was dramatically increased following Russia’s invasion, a significant downsizing of U.S. forces in Europe for redeployment to other regions could severely weaken deterrence and embolden a revanchist Russia.
Second, the United States should permanently station a U.S. Army armored brigade combat team (ABCT) in Poland to strengthen deterrence, reassure the United States’ Eastern European allies, and pursue a more sustainable posture. Shifting the current rotational ABCT from Operation Atlantic Resolve to a permanent presence in Poland should be part of a 4+2 posture in Europe. This setup would include four U.S. BCTs—three forward-stationed BCTs in Poland, Italy, and Germany, along with one rotational BCT in Romania—and two divisional headquarters, in Germany and Poland. Moreover, a permanent forward-stationed ABCT in Europe would be less costly from both a fiscal and readiness perspective than the current rotational deployment model.
Third, the United States needs to continue pressing European militaries to increase their own capabilities to deter Russia and—if deterrence fails—to help fight and win a major power war, particularly given U.S. interests and defense objectives in the Indo-Pacific. As it currently stands, European militaries would likely have difficulty conducting operations at the high end of the conflict continuum without significant assistance from the United States. European states still lack sufficient capabilities in such areas as combat support, including short-range air defense and long-range indirect fires; airlift and other logistical means of transporting troops and material; quantity, quality, and capabilities of ground forces, especially heavy maneuver forces; and sufficient quantities of long-range precision strike munitions, such as the Long Range Anti-Ship Missile (LRASM).
The rest of this brief is divided into five sections. The first outlines historical trends in U.S. force posture in Europe. The second section assesses the future threat landscape. The third summarizes U.S. interests and defense objectives in Europe. The fourth section details the primary components of a robust force posture in Europe. The fifth provides a brief conclusion.
Historical Trends and Current Posture
The United States’ military posture in Europe has evolved considerably from the end of World War II to the present. Changes to the number and types of capabilities of U.S. forces in Europe have been driven by several factors, including the perception of the threat posed by the Soviet Union and Russia to the United States and its European allies, the relative balance of military capabilities between NATO and the Warsaw Pact, the evolution of U.S. strategy and political considerations, and the relationship between the United States and its allies.
Following World War II, total U.S. end strength fell from over 12 million personnel in 1945 to just 1.4 million by 1948, despite rising tensions between the West and Soviet Union. U.S. end strength in Europe meanwhile fell to approximately 150,000 by the late 1940s. The adoption of NSC-68 under the Truman administration following the Korean War had the practical effect of waking the United States and Europe up to the military dimensions of the Cold War as the United States and NATO took steps to significantly increase their military presence. However, NATO members failed to meet the ambitious goals agreed to in Lisbon in 1952. During this period, the U.S. military pushed for the creation of an integrated NATO command structure and took on critical NATO staff roles, including a U.S. general as the supreme allied commander, Europe (SACEUR). The United States also established U.S. European Command (EUCOM) in August 1952.
Under President Eisenhower’s New Look strategy, the United States reduced the role of conventional forces in Europe to a “tripwire” and “delaying force” as deterrence relied on massive retaliation. The Kennedy administration’s “flexible response” strategy sought a more “balanced” approach in the belief that massive retaliation was no longer credible given advances in Soviet nuclear capabilities. The Soviet Union’s 1976 deployment of SS-20 intermediate-range missiles led the Carter administration to pursue its dual-track strategy, which called for deploying additional missiles in Europe—specifically, Pershing 2 ballistic missiles and ground-launched cruise missiles—while simultaneously pursuing arms control talks. Ronald Reagan continued with the deployment of the Pershing 2 missiles in 1983, while also building up U.S. forces in Europe.
Following the end of the Cold War, the United States significantly reduced its military presence in Europe. The Clinton administration planned for a final end strength of 100,000 personnel by 1996, but only reached a low of 113,000 in 1997 due to involvement in the Balkan Wars. The Bush administration sought further cuts to U.S. posture as the number of U.S. service members in Europe fell to 66,000 in 2008, and end strength reached a post–World War II low of 63,000 in 2013 under the Obama administration.
Russia’s seizure of Crimea and its related military operations in western Ukraine in 2014, along with its full-scale invasion of Ukraine in 2022, prompted the United States to bolster its military presence in Europe. In 2017, the U.S. Department of Defense announced the beginning of a continuous armored brigade combat team (ABCT) rotational presence in Europe and back-to-back rotations of U.S. troops and equipment to Europe. By 2023, the 7,000-person rotational force included four elements: a division headquarters located in Poznan, Poland; a combat aviation brigade; an ABCT; and a sustainment task force. Following Russia’s 2022 invasion, U.S. end strength in Europe grew significantly to over 100,000 personnel as additional forces were deployed, including another ABCT, a High-Mobility Artillery Rocket System (HIMARS) battalion, and KC-135 refueling aircraft, among other forces.
In terms of ground forces, the United States currently maintains a 5+2 posture consisting of five brigade combat teams—two IBCTs (one permanent and one rotational), one permanent SBCT, and two rotational ABCTs—and two headquarters. This represents an increase from the previous 3+1 model—one permanent IBCT, one permanent SBCT, and one rotational ABCT plus one headquarters in place prior to Russia’s 2022 invasion. The permanent units include the 2nd Cavalry Regiment Stryker brigade combat team (SBCT) headquartered in Vilseck, Germany, and the 173rd Airborne Brigade stationed across Vincenza, Italy, and Grafenwoehr, Germany, as well as the forward-stationed 12th Combat Aviation Brigade. The rotational ABCT, established in the wake of Russia’s 2014 invasion of Ukraine, serves as part of Operation Atlantic Resolve, which deploys approximately 7,000 U.S. Army personnel (including the ABCT, plus a combat aviation brigade, sustainment task force, and forward division headquarters) to Europe on nine-month rotations.
U.S. air capabilities include fighter, attack, rotary-wing, tanker, and transport aircraft that perform close air support, air interdiction, air defense, in-flight refueling, long-range transport, and support of maritime operations. These forces include seven squadrons of fighter aircraft.
The Evolving Threat Landscape
Looking forward, Russia will remain the most significant threat to Europe. Today, NATO enjoys a strong conventional and nuclear deterrent. In the event of a potential near-term Russian attack against NATO’s eastern flank, however unlikely, there are several factors in NATO’s favor: the inherent advantage of the defense, the force-to-space ratio problem for Russia, the limited avenues of approach from Russia into Eastern Europe, and the qualitative superiority of NATO forces. In addition, NATO retains a robust nuclear deterrent.
Nevertheless, Russia has the will and intentions to threaten one or more NATO countries, and it is steadily rebuilding its military capabilities thanks, in part, to aid from China, Iran, and North Korea. Russian military thinking is dominated by a view that the United States is—and will remain—Moscow’s main enemy (главный враг) for the foreseeable future. This view of the United States as the primary adversary has increased since the 2022 invasion. Russian political and military leaders assess that Russia’s struggles in Ukraine have been largely due to aid from the United States and the broader NATO alliance, which Russian leaders interpret as direct participation in the war. In addition, Russian leaders likely believe that the United States is attempting to expand its power, further encircle Russia, and weaken Russia militarily, politically, and economically. These sentiments will make Russia a dangerous enemy over the next several years and will likely further drive Moscow’s desire to reconstitute its military as rapidly as possible, prepare to fight the West if deterrence fails, and engage in irregular and hybrid activities.
In addition, at least four factors could change the military balance in Europe over the next decade. First, the United States could become overstretched due to a major theater war in another region, such as against China in the Indo-Pacific. European conventional and logistical capabilities are limited—particularly for high-end war—creating potential vulnerabilities if the United States were to withdraw significant air, naval, and ground forces from the region. Second, Russia could continue to rebuild its military capabilities over the next several years with additional help from China, Iran, North Korea, and other countries. Third, there could be a significant decline in U.S. or European political will to build the military capabilities sufficient to deter Russia and a decrease in commitment to NATO. The drop in political will could be caused by a change in political leaders, domestic priorities, financial constraints, or other factors. Fourth, there are other potential wildcards that could impact the threat environment, such as a Russian leadership change or Russian use of a nuclear weapon.
European military capabilities remain concerning. European states still lack sufficient heavy maneuver forces, airlift, naval combatants, and support capabilities, such as logistics and fire support. Although European allies and partners of the United States plan to improve these capabilities by 2030 as part of a greater NATO-agreed initiative, it is unclear whether they will be successful. European challenges are particularly notable when considering a large-scale, high-end conflict at short notice given most European countries’ persistent readiness challenges.
In addition, several European countries will likely struggle to field units because of manpower shortages. For example, the shrinking forces of both the United Kingdom and Germany reflect an overall trend affecting not only Europe but also the United States and Canada in trying to recruit and retain an all-volunteer, professional armed force. This is a challenge that needs to be addressed by all Western nations. Without adequate active-duty volunteers, many national leaders will need to consider whether a greater reliance on reservists will be needed to meet force goals and operational requirements. Additionally, consideration may need to be given to reinstitute conscription in some form—like Finland has done—to have a minimally trained reserve force capable of being called up and deployed if needed.
Despite these wildcards, Russia will likely constitute a serious threat to the United States and Europe for the foreseeable future. Russian president Vladimir Putin retains the political will and intentions to expand Russian power abroad, and Russia is reconstituting its military capabilities with help from China, Iran, and North Korea. The key takeaway is that neither today’s military balance nor deterrence is guaranteed to hold.
U.S. Interests and Defense Objectives
U.S. interests in Europe are significant, and U.S. allies and partners in Europe share the United States’ democratic values and account for significant military, economic, and technological power. Since its establishment in the 1949 Washington Treaty, NATO has been the lynchpin of U.S. security in Europe. The bedrock of NATO is a collective defense provision—an attack on one is an attack on all—that was codified in Article V of the Washington Treaty. During the Cold War, the alliance served as the primary bulwark against the expansion of the Soviet Union. Following the Soviet Union’s collapse, NATO became the major framework for organizing transatlantic efforts on collective security matters, including military interventions in the Balkans, Afghanistan, and Libya. In addition, several former Soviet republics (such as Estonia, Latvia, and Lithuania) and members of the Soviet-aligned Warsaw Pact (such as Bulgaria, the Czech Republic, Hungary, Poland, Romania, and Slovakia) later became NATO members.
These treaty relationships have benefited the United States in several ways. One is supporting U.S. leadership. As a result of the United States’ central role in transatlantic and international relations that, in many ways, NATO has cemented, Americans have enjoyed unprecedented economic prosperity and freedom. Successive U.S. governments have been afforded both de facto and de jure privileged status related to such issues as trade partnerships and access to bases in large part because of the outsized role that the country plays in the defense of its allies. For example, the United States would not have been able to prosecute expeditionary and counterterrorism operations in the Middle East and Africa were it not for the bases and prepositioned equipment that the United States has been able to maintain on allied soil in Europe.
Another long-standing reason for U.S. engagement in Europe is to enable U.S. strategic depth. The United States’ geographic location, protected by both the Atlantic and Pacific Oceans, no longer provides the same security as in previous decades because of advances in long-range strike, cyber operations, space, and other technological developments. As a result, it is prudent to station U.S. forces overseas to contend with adversary aggression—if not outright conflict—far from the U.S. homeland. Not only does this make the U.S. homeland less vulnerable to outright war, but forward presence is also relatively cost effective.
Finally, the NATO alliance today affords the United States strategic flexibility. Most of the United States’ main security challenges—from China and Russia to Iran and terrorism—cannot be tackled by one state alone, not even the United States. Allies are critical. They enable flexible cooperation and consultation on any number of strategic issues as they arise.
The United States has interests elsewhere in the world. In particular, China will likely be the United States’ main global competitor. China poses a challenge to the United States around the globe because of its expanding conventional and nuclear capabilities, irregular warfare and gray zone activities, technological and economic competitiveness, and “wolf warrior” diplomacy. The United States has important interests in other regions as well, including in the Middle East, Asia, Africa, and Latin America. But it is a false dichotomy to argue that the United States needs to choose between these interests—especially between China and Russia. Both are authoritarian regimes cooperating with each other on two major axes. Beijing and Moscow have deepened their military, economic, and diplomatic ties since Russia’s invasion of Ukraine. The United States should develop a two-front strategy that works with allies and partners to counter China and Russia.
Overall, the United States currently has several broad security interests in Europe, which will likely persist over the next decade:
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Protect the U.S. homeland and the security of the American people, including from threats emanating from Europe;
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Promote and expand U.S. economic prosperity and opportunity;
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Realize and defend the democratic values at the heart of the American way of life; and
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Defend and support the United States’ European allies and partners.
Based on these interests, the United States has several defense objectives in Europe:
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Deter and defeat conventional and nuclear-armed conflict directed against the U.S. homeland and U.S. allies, as well as coerce, persuade, and influence adversary behavior;
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Counter irregular and gray zone activities, as well as compete effectively below the threshold of conventional conflict using both defensive and offensive means;
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Counter terrorist and other transnational threats;
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Deter and prevent state and non-state actors from acquiring, proliferating, or using weapons of mass destruction; and
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Maintain access to trade routes and global commons.
A Posture of Forward Defense
Based on these interests and objectives, this section examines potential changes to U.S. military posture in Europe over the next five years. The recommendations outlined below seek to enhance U.S. military posture from its levels before the 2022 Russian invasion of Ukraine. The benefits of this strategy are twofold.
First, this posture strengthens the ability of the United States and NATO to deter and repel Russian aggression on the continent. Second, this strategy pursues more sustainable policies by shifting the presence of U.S. ground forces from rotational deployments to permanent, forward-stationed forces and articulating trade-offs and limitations with other strategic priorities, such as competition with China in the Indo-Pacific region.
Ground Forces
The nature of operations in Ukraine and the threat from Russia illustrate the continued significance of ground forces in combat in the European theater for deterrence and warfighting. There are several types of capabilities important for achieving U.S. defense objectives:
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Army units, including ABCTs;
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Main battle tanks, armored personnel carriers, and infantry fighting vehicles;
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Integrated air and missile defense systems;
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Long-range fires;
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Manned and unmanned aircraft;
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Multi-domain command and control; and
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Additional investments and equipment—including logistics—such as munitions stockpiles, spare parts, hardened facilities, and improved lines of communication.
Based on Russia’s efforts to revitalize its military capabilities, the United States should consequently take steps to strengthen its presence from pre-February 2022 levels by increasing the number of permanent forward-stationed maneuver forces to deter and effectively respond to Russian aggression. That increase entails shifting the rotational ABCT associated with Operation Atlantic Resolve (along with the associated combat aviation brigade) to a permanent, forward-stationed ABCT headquartered in Poland. The United States should also maintain its current rotational infantry brigade combat team (IBCT) presence in Romania, as well as rotational deployments to the Baltic states in the near term and incorporate them into Operation Atlantic Resolve under the command of the V Corps headquarters. However, the requirement for these rotational forces may shift depending on changes to the threat environment.
These changes to the posture of U.S. ground forces would shift the U.S. Army to a posture model of four total brigade combat teams in Europe (three permanent, forward-stationed BCTs and one rotational BCT) plus two headquarters in Germany and Poland—a four BCTs + two headquarters model—and away from both the 3+1 model in place prior to the war in Ukraine and the current 5+2 model. The 4+2 model would also include the permanent forward-basing of two combat aviation brigades (the existing 12th Combat Aviation Brigade plus another). Prior to Russia’s February 2022 invasion, the United States maintained two permanent, forward-stationed BCTs in Europe plus one rotational BCT.
The recommended changes in this analysis for a 4+2 model would maintain the permanent SBCT in Germany and IBCT in Italy and Germany; create a permanent, forward-stationed ABCT at a new base in Poland; maintain the rotational IBCT in Romania; and maintain two permanent headquarters in Germany and Poland.
Forward-stationing an ABCT in Poland offers several benefits to maintaining U.S. interests and achieving objectives in Europe, including (1) providing a credible force to swiftly respond to acts of Russian aggression against NATO partners; (2) reassuring allies of U.S. commitment while building interoperability with partner forces; and (3) enhancing the general readiness of U.S. forces at large and reducing costs in the long run. Poland would provide the most practical and beneficial location to establish a new military base for an ABCT from both operational and political perspectives as it already hosts the V Corps Forward Command Post Headquarters, an Army garrison, and sufficient sustainment capabilities—the “first permanent stationing of U.S. forces on NATO’s eastern flank.”
More critically, forward-stationing U.S. units in Poland would facilitate the speed of assembly and movement for U.S. operations in Europe, providing a combat-credible ABCT force to quickly counter Russian aggression. This capability would play a particularly major role in deterring or responding to a contingency in the Baltic states, where Russian forces could threaten to cut off or slow the access of U.S. and NATO forces by closing the Suwalki Gap—the 40-mile gap between Kaliningrad and Belarus where Lithuania borders Poland. Poland also offers greater strategic depth than alternative locations, such as the Baltic states, and possesses interconnected rail lines with the rest of Europe that would ease resupply and reinforcement efforts.
Forward-stationing additional U.S. forces would also enhance interoperability with allied forces and society, while lowering costs from a force planning and budgetary perspective. In terms of force-generation, an enduring and constant rotational ABCT presence in Europe for a nine-month deployment requires three total ABCTs. As an illustrative example, U.S.-based ABCT-1 must be training and preparing to deploy to replace ABCT-2 currently in Europe. ABCT-3, also U.S.-based, after recently ending its nine-month deployment, must then recover and begin training to deploy following ABCT-1’s tour overseas. This rotational model eats up more of the Army’s force structure and long-term readiness than one forward-stationed unit would.
From a fiscal cost perspective, establishing a new base in Poland would initially have high budgetary costs and take roughly seven years to put in place. However, operation and sustainment costs would be significantly lower than those of a rotational force. A forward-stationed ABCT incurs 75 percent of the additional operational tempo (OPTEMPO) costs that a rotationally deployed ABCT would, and it also generates savings over time. Moreover, given the cost of moving their equipment, ABCTs are the most expensive unit to rotationally deploy, suggesting that IBCTs or SBCTs are better suited to the rotational deployment model.
Air Combat Forces
In terms of air combat capabilities, a forward defense posture includes maintaining all seven forward-deployed fighter squadrons currently based in Europe and adding an additional F-16 squadron to Spangdahlem Air Base. Four squadrons are already based at RAF Lakenheath in the United Kingdom under the 48th Fighter Air Wing, including two squadrons of F-35A aircraft and two F-15E squadrons. Two squadrons of F-16 aircraft are stationed at Aviano Air Base in Italy under the 31st Fighter Wing, and one additional F-16 squadron is currently stationed at Spangdahlem Air Base in Germany under the 52nd Fighter Wing. While stationed out of their respective bases, these units have often been forward deployed to NATO’s eastern flank to provide additional posture amid the war in Ukraine. Forward-stationed forces are supplemented by deployments of U.S.-based fighter aircraft—including active-duty, reserve, and Air National Guard assets—to enhance posture; such deployments have increased in the lead-up to and throughout the Ukraine conflict.
Forward-deployed F-35 squadrons enhance the capabilities of U.S. and allied forces to establish air superiority against robust and experienced Russian integrated air defense systems (IADS). F-35 aircraft can also collect electronic signals from and compile a picture of hostile and friendly forces in an area. However, given requirements for the Indo-Pacific region, adding another F-35 squadron to the two currently stationed at RAF Lakenheath is not optimal.
Instead, forward stationing an additional F-16 squadron at Spangdahlem Air Base would provide greater short-term combat capacity as allied F-35 squadrons come online. Additional permanently based fifth-generation squadrons in Europe may be more likely to come as future replacements for the Air Force’s F-15E squadrons, which the service plans to cut by more than half by 2028. However, U.S. Air Forces Europe should supplement these aircraft with deployments of U.S.-based fifth-generation squadrons of fighter aircraft—either F-35 or F-22 aircraft—as demanded by the threat environment.
To further maximize flexibility, U.S. air combat forces based in or deployed to Europe should also be prepared to surge to the Indo-Pacific in the event of a contingency. The Air Force has already leveraged EUCOM assets to fill capability gaps in the Indo-Pacific with the temporary transfer of F-16 aircraft from the 52nd Fighter Wing at Spangdahlem Air Base to Kadena Air Base in Japan amid the return of its F-15C/D fighter aircraft to the United States.
Naval Forces
To achieve a posture of forward defense, the United States should enhance its naval presence in the Baltic Sea region with small surface combatants and unmanned vessels through 2030 to improve interoperability with allies and partners and to deter Russian aggression. Russia still maintains a sizeable presence in the region. U.S. ships should conduct more frequent port visits, including both FDNF-E patrols and deployments of U.S.-based assets, as well as bilateral and multilateral exercises.
The United States should also act in coordination with its NATO allies to tackle several mission sets, including anti-submarine warfare in the Baltic and North Seas, which have been much neglected. NATO has increased its joint anti-submarine warfare exercises among allied forces, including Operation Dynamic Mongoose in the North Atlantic in 2022 and Dynamic Manta off the coast of Italy in 2023. The United States could also pursue greater coordination with allies’ carrier and amphibious capabilities to bolster presence among competing demands from other theaters.
The U.S. Navy could supplement existing NATO anti-submarine warfare capabilities by developing and deploying additional systems to the region. One option is homeporting the U.S. Navy’s Littoral Combat Ship, which has anti-submarine warfare capabilities, in German ports to provide improved situational awareness in the Baltics, or alternatively deploying Constellation-class frigates, which also have anti-submarine warfare capabilities, once they are operational. However, the operational requirements for the presence of surface ships and submarines in the Indo-Pacific should take priority over Baltic deployments.
Given Indo-Pacific demand for naval forces, the Navy could leverage its developing unmanned surface and undersea vessels for anti-submarine warfare and additional missions in the Baltic Sea. Pioneered under the Fifth Fleet’s Task Force 59 in U.S. Central Command, the Navy recently announced its intention to deploy these capabilities to the broader fleet beginning with the Fourth Fleet under U.S. Southern Command in the summer of 2023. The United States and partners should also increase their number of sonobuoys and static hydrophone networks to track subsurface threats.
In the Baltic region, the U.S. Navy and NATO allies should prioritize three additional missions. They should develop a plan to tackle hybrid gray zone threats to undersea cables and pipelines and other infrastructure that Russia may target to disrupt the flow of commerce, energy, and information. Furthermore, the United States and NATO should plan to leverage the extensive mining and demining capabilities of new members Finland and Sweden in the event of a possible conflict with Russia that threatens naval deployments and the commercial shipping of partners and allies. Finally, the United States and NATO should anticipate the use of anti-ship cruise missiles in a conflict with Russia and seek to neutralize this threat through the coordination of the Baltic Air Policing mission and Allied Maritime Command as part of the missile defense and suppression mission.
In the Black Sea, the United States should work with its regional NATO allies and partners to enhance its maritime domain awareness. The United States and the NATO alliance should encourage regional partners to cooperate and modernize their military capabilities, including by strengthening sea power in ways that are consistent with the Montreux Convention.
The Arctic represents another vital region for U.S. maritime interests. The United States should expand its capabilities and posture in the Arctic, particularly through the U.S. Coast Guard. The expansion of the United States’ Arctic posture and capabilities should be pursued as rapidly as possible to counter Russian and Chinese security interests in the region. As the Coast Guard awaits delivery of new icebreakers, the military more broadly should seek to enhance cooperation with Arctic allies through joint operations and combined exercises and training.
Logistics and Enablers
This section examines several types of logistics and enablers, including prepositioned equipment and munitions stockpiles; intelligence, surveillance, and reconnaissance; integrated air and missile defense; and infrastructure and mobility.
Prepositioned Equipment and Munitions Stockpiles: The United States should take steps to bolster its prepositioned equipment and munitions stocks in Europe to enhance the readiness of U.S. forces in the event of a contingency with Russia. The Army currently maintains its Army Prepositioned Stock-2 (APS-2) across four sites in three different countries (Germany, Belgium, and the Netherlands) with enough material to equip two ABCTs; a fifth APS-2 site is planned for Poland. In March 2022, the Army issued some of this stock to the 1st ABCT, 3rd Infantry Division in the wake of Russia’s invasion of Ukraine. While APS-2 stocks have been bolstered by funding from the European Deterrence Initiative, the Army should take additional steps to improve the readiness of this equipment and the forces overseeing it to ensure that U.S. forces arriving in theater will rapidly receive capable equipment. A DOD inspector general investigation found that some materiel provided from APS-2 was “non-fully mission capable” and that “maintenance and coordination shortfalls occurred.” The Marine Corps also maintains prepositioned equipment in central Norway under the Marine Corps Prepositioning Program-Norway (MCPP-N).
In addition to enhancing prepositioned equipment, the DOD should ensure that EUCOM has the appropriate inventories of munitions in the region. The war in Ukraine has demonstrated the importance of long-range artillery, and U.S. and NATO forces must have enough missiles and munitions in theater to contend with and counter Russian forces. That includes munitions for the Air Force, which should develop plans to maintain weapons for aircraft operating under the agile combat employment (ACE) concept at forward locations, and the Army’s EUCOM munitions starter stocks, which preposition key munitions—including Patriot Missile Segment Enhancement—in Europe for use in the event of a contingency.
Intelligence, Surveillance, and Reconnaissance (ISR): The demand for U.S. ISR assets will only increase as the U.S. military expands its missions and operations in the Indo-Pacific and as the Russian military reconstitutes its capabilities on NATO’s eastern flank. While the United States should prioritize the Indo-Pacific, the DOD should maximize its available ISR assets for use by both EUCOM and U.S. Indo-Pacific Command. The DOD is currently seeking to modernize its ISR capabilities, with plans to retire the RQ-4 by fiscal year (FY) 2027 and the MQ-9 by FY 2035. However, the DOD and the services should ensure that any gaps in ISR coverage are limited. The DOD should also leverage commercial capabilities to cover any gaps until requirements are established and new platforms are deployed.
Space-based ISR assets will play a major role in both covering gaps and supplementing ISR provided by traditional airborne assets. Commercial satellite imagery has already been used by NATO to fill gaps in coverage and has played a major role in identifying Russian military movements in the lead-up to the 2022 invasion of Ukraine. In the next few years, the United States should further leverage commercial satellite imagery to bolster its ISR capabilities in Europe. Over the long term, however, the DOD should ultimately determine the appropriate balance between leasing commercial services and establishing its own systems to ensure sustainable and reliable coverage.
Integrated Air and Missile Defense: The adoption of some of the recommendations here will necessitate changes to the U.S. air and missile defense posture, including the permanent basing of an ABCT in Poland, which would require an investment in air and missile defense capabilities given its proximity to Russia. If a new base is established, the United States should consider shifting the headquarters of the 10th Army Air and Missile Defense Command from Rhine Ordnance Barracks in Germany eastward. If the Army chooses not to move the entire command to Poland, it should prioritize shifting the battalion headquarters of the 5th Battalion, 7th Air Defense Artillery Regiment—which provides command and control operations of Patriot batteries—and the 5th Battalion, 4th Air Defense Artillery Regiment with its short-range air defense capabilities.
From a broader force-planning perspective, the Army should prioritize the development of additional Patriot battalions, which operate at the highest OPTEMPO of all Army units and are in high demand from multiple combatant commands. Given their value in potential conflicts with China and Russia, the Army should create additional units to limit the stress on and the degradation of the readiness of existing units, particularly given the lack of European capabilities in this area.
In terms of ballistic missile defense, the United States should maintain its current posture and force structure in line with Operation Atlantic Sentry. Relevant units include the five Aegis destroyers homeported in Rota, Spain (with a sixth planned to arrive in 2026), along with the two Aegis Ashore sites based in Romania and Poland.
Infrastructure, Mobility, and Access: The United States, in partnership with host nations and other NATO allies, should take steps to improve military infrastructure and mobility to ensure ease of access, transportation, and reliable communications throughout the European theater. These include enhancements to infrastructure on both U.S. bases and in partner countries, such as the installation of fiber-optic cables and improvements to railways, road networks, and bridges. The DOD and the European Defence Agency (EDA) have identified military mobility as one area of collaboration under an administrative arrangement reached in April 2023 (see security cooperation section below).
Furthermore, the United States should continue to update its security and defense cooperation agreements with its partners and allies to ensure ease of access throughout the European theater. In December 2023, the United States reached new agreements with Denmark, Estonia, Finland, Latvia, Lithuania, and Sweden that provided U.S. forces with access to bases and other infrastructure in those countries.
Nuclear Posture
The United States should continue with planned nuclear modernization efforts, exercises, and scheduled deployments of assets to the European theater to bolster its deterrent capabilities and reassure allies. The United States currently deploys 100 tactical bombs—the B61-3 and B61-4 gravity bombs—in air bases across five countries in Europe. Under current U.S. nuclear-sharing policy, control over those bombs is maintained by the U.S. Air Force, but seven countries contribute dual-capable aircraft to the mission (Belgium, Germany, Greece, Italy, the Netherlands, Turkey, and the United States) and four air forces (from Belgium, Germany, Italy, and the Netherlands) are assigned an active nuclear strike role with those weapons in the event that a nuclear mission is approved.
The United States is currently in the process of modernizing its gravity bombs, with the new B61-12 having begun full-scale production in 2022; deployment originally was planned for the spring of 2023 but has been delayed. NATO is also modernizing its nuclear weapons storage facilities, including making upgrades to command and control structures and base security.
The U.S. military and NATO should also continue to conduct exercises with nuclear-capable platforms, including Bomber Task Force missions, to enhance readiness and assure allies of U.S. support. These include the annual NATO Steadfast Noon exercise, which practices nuclear sharing. However, such exercises should occur on a regularly scheduled timeline to ensure consistency and to limit the potential for escalation with or misinterpretation by Russia. There is no evidence that unscheduled Bomber Task Force deployments conducted under the dynamic force employment model offered additional deterrent value.
Cyber and Space
In the cyber and space domains, U.S. forces should take steps to enhance the security and resilience of their own systems and networks while simultaneously assisting European partners and allies in securing their own capabilities. U.S. Cyber Command should deploy additional “hunt forward” teams to Europe in line with its “defend forward” strategy to counter threats to U.S. forces and allies from Russia and Russian-backed groups. The United States should further define its authorities for and consider expanding its conduct of offensive cyber operations against Russian forces, particularly in the event that the conflict in Ukraine and Russian cyberattacks continue.
The United States should also expand deployments of U.S. Space Force units and personnel to Europe and define their role within NATO. The service is currently standing up its own component to operate in EUCOM. Space Force units can play a major role in supporting forward-deployed U.S. forces by preventing enemy interference and maintaining open lines of satellite communication. Additionally, space-based ISR assets will continue to play a major role in the European theater, and the U.S. military should further leverage commercial capabilities to fill gaps.
Finally, U.S. forces should enhance redundancy, in addition to improving the resilience of U.S. assets and networks in terms of both software and hardware. Establishing clear fallback options for communications and ISR in the event of a contingency is vital to ensuring the survivability of networks.
Security Cooperation
In addition to maintaining and bolstering traditional partner capacity-building efforts, the DOD, in tandem with EUCOM and the U.S. Department of State, should adopt a broader approach to security cooperation in the region that supports NATO allies and other European partners in developing and acquiring advanced military capabilities to increase their national and collective NATO force posture and lessen their reliance on U.S. units and platforms.
The DOD should consider standing up a new organization within EUCOM to coordinate broader U.S. security cooperation efforts in Europe and to help close quantitative and qualitative gaps within European militaries that drive their reliance on U.S. forces in some areas. This organization—with representation from the services, the Office of the Under Secretary of Defense for Policy, and the Defense Security Cooperation Agency, and in coordination with the State Department—would directly interface with NATO headquarters and allied militaries to manage requests for security assistance and arms sales, as well as to provide guidance on the development of new capabilities and coordinate information sharing, as needed.
The DOD has already taken some steps to bolster cooperation efforts and information sharing with its April 2023 administrative arrangement with the EDA, which provides a framework for the United States and the EDA to “exchange information and explore collaborative activities falling within the scope of the [EDA’s] mission,” with a focus on areas including supply chain issues, military mobility, and the impact of climate change on defense activities. However, the terms of the agreement specifically preclude “research and technology” from the scope of the arrangement.
Conclusion
The U.S. military presence in Europe will likely remain contentious for several reasons. Numerous U.S. policymakers and analysts assess China to be the most significant threat to the United States for the foreseeable future and argue that the United States should focus the bulk of its military posture and attention—including its military air, naval, and maritime forces—toward and into the Indo-Pacific. In addition, some policymakers and analysts support decreasing the U.S. presence in Europe because some European governments have generally failed to increase their defense budgets or focus on high-end military capabilities. Finally, some contend that the United States should focus on problems at home, such as combatting immigration, improving health care, and stemming the production, trafficking, and use of such drugs as fentanyl.
There is some validity in all of these points. China is a major threat, European governments need to spend more (and spend more effectively) on defense, and the United States needs to better address a wide range of challenges at home. Yet, as this analysis maintains, the United States has significant and enduring interests in Europe that will require a force posture of forward defense. A notable decline in the United States’ force posture in Europe would likely be significant and dangerous for U.S. national security in several ways.
First, it would embolden a revanchist Moscow and undermine deterrence in Europe. President Vladimir Putin and other Russian leaders would likely see a declining U.S. force posture in Europe as a sign of weakening U.S. resolve and potentially declining power. The United States’ limited response following Russia’s illegal annexation of Crimea in 2014 and military action in eastern Ukraine later that year likely encouraged Russia to take future action. Second, a deteriorating U.S. posture would likely embolden other U.S. adversaries, such as China, and heighten concerns among U.S. allies and partners in Asia about U.S. resolve. The views in Taipei, the most likely flashpoint with China, are striking. Some of Taiwan’s national security leaders have warned that a reduced U.S. commitment to Europe—including aid to Ukraine—would heighten Taiwanese concerns about U.S. resolve. Only 34 percent of those in Taiwan in 2023 believed that the United States is a trustworthy country, a decline of more than 11 percentage points from 2021. Researchers concluded that the drop was partly caused by a perception that U.S. resolve is weakening in Europe, including in Ukraine.
Europe remains a vital region for the United States. The last two U.S. national security and national defense strategies have prioritized China as the main global threat. But Russia’s brutal invasion of Ukraine, its continuing aggression, and its growing cooperation with China are stark reminders that the United States has significant and enduring interests in Europe as well.
Seth G. Jones is president of the Defense and Security Department and Harold Brown Chair at the Center for Strategic and International Studies (CSIS) in Washington, D.C.
Seamus P. Daniels is the fellow for Defense Budget Analysis in the Defense and Security Department at CSIS.