The U.S. Review of Troop Realignment in Europe and Pressure on Allies for Burden-Sharing: Analysis and Policy Options

Executive Summary

The Pentagon’s ongoing review of U.S. troops in Europe is the European implementation of the resource reallocation prioritizing the Indo-Pacific, a policy codified in the second-term Trump administration’s National Defense Strategy. The review is expected to take concrete shape following the submission of a draft with four reduction options on November 6. The criteria for these reductions will reportedly include not only the scale of defense spending but also the level of guaranteed access to bases and airspace and cooperation with U.S. foreign policy, such as during the war with Iran. Consequently, concerns are growing within NATO about a breakdown of equity and the potential for selective, differentiated reductions. Eastern European countries like Hungary and Romania have preemptively responded with a targeted offer to share base operating costs instead of increasing their total defense budgets. This indicates that the essence of the “proof of cooperation” demanded by the United States lies not in total budget figures but in concrete actions that alleviate the U.S. burden. However, a more cautious view also holds that congressional budgetary authority, backlash from European nations, and Trump’s own political calculations could prevent a rapid withdrawal, making the realignment likely a matter of pace and sequence. South Korea should treat this case as a leading indicator for its Special Measures Agreement (SMA) negotiations and discussions on extended deterrence. It needs to move beyond the framework of increasing its total financial contribution and prepare a package of specific alternatives, including investments in missile defense and unmanned systems and measures to enhance base survivability.

I. Situational Analysis

U.S. Review of Troop Realignment in Europe: A Situational Analysis

1. Background and Developments

The Pentagon’s review of U.S. troops in Europe was a step foreshadowed in the second-term Trump administration’s National Defense Strategy, released earlier this year [6][7]. The strategy codifies the premise that the United States lacks the financial and industrial capacity to respond to multiple threats simultaneously and identifies increased burden-sharing by allies as a key means of implementation [2]. In May, the Trump administration announced it would withdraw some U.S. military assets from the NATO Force Model and would no longer serve as the primary guarantor of European security in the event of a full-scale conventional war with Russia [4]. The current review is an extension of these moves.

This six-month review, officially launched in June, was initially targeted for completion in December. However, the deadline for submitting a draft of at least four reduction options to Secretary of Defense Pete Hegseth has been moved up to November 6 [8][12][14]. The criteria for troop redeployment decisions will reportedly include not only the scale of defense spending but also the level of access a host nation guarantees to U.S. bases and airspace, and its degree of cooperation with U.S. foreign policy, for instance on the war with Iran [1]. Citing a document obtained by Reuters, reports from Tanzania’s The Citizen and Al-Monitor indicate that concerns are spreading within NATO that countries judged by Trump as unsupportive of the U.S. during the Iran-Israel war could be targeted for reductions [8][12].

2. Current Situation

On August 27 in Brussels, Under Secretary of Defense for Policy Elbridge Colby personally explained the direction of the review to NATO allies [15][5]. The Associated Press reported that Colby pressed the allies to prove that they are truly taking the lead in Europe’s defense [5]. According to the AP’s analysis, this pressure comes as Washington is shifting its security focus to the Indo-Pacific and issues closer to the U.S. homeland [5].

Eastern European countries have responded preemptively. The Hungarian outlet HVG, citing Bloomberg, reported that Central and Eastern European NATO members planned to propose to Colby at the August 27 Brussels meeting that they would partially cover the operating costs of U.S. bases on their soil [16]. Telex reported that Romania is moving to shoulder more of the costs of the U.S. troop presence to prevent further withdrawals by the Trump administration [19]. This highlights the desperation of Eastern European nations, which fear the withdrawal of U.S. military assets from their territory more than the burden-sharing percentages themselves.

Meanwhile, a more cautious view is emerging within the United States, suggesting the review will not lead to an immediate, large-scale troop withdrawal. Foreign Policy has analyzed that Congress, European nations, and even President Trump’s own political calculations could act as a brake on any drastic changes [10]. The article suggests that the actual troop redeployment is becoming a matter of internal military coordination over which units to maintain and which to withdraw [10].

3. Key Actors and Positions

The Pentagon (Under Secretary of Defense for Policy Colby, Secretary of Defense Hegseth)is the main actor implementing this review. Colby is a key figure pushing to translate the Indo-Pacific-first strategy into defense budget and troop deployment decisions, and he has previously used similar logic to press allies for greater investment in their own defense, notably during a visit to the Philippines [2]. Secretary Hegseth is scheduled to receive a report on at least four options by November 6, which will inform the final decision in December [8][12][14].

Eastern European NATO Members(e.g., Hungary, Romania, Poland) are attempting to avoid being targeted for reductions by offering to partially share the costs of the U.S. troop presence [16][19]. For these countries, the U.S. military presence is a critical security issue directly tied to their geographic proximity to Russia, and cost-sharing is being used as leverage to prevent troop cuts.

Key Western European Nations (e.g., Germany, France)have made limited direct statements on this issue. However, the Brookings Institution reports that they are engaged in workshop-level discussions about how a “Europeanized NATO” would manage European defense amid reduced U.S. support [4]. A previous EAI analysis assessed that a unified response is likely to remain merely declarative, owing to differing threat perceptions between France and Germany and the parallel institutional structures of the EU and NATO [13].

U.S. Congress and Defense Industryare seen as a potential check on a rapid withdrawal. Foreign Policy suggests that political constraints from Congress could limit the actual scale of reductions [10]. At the same time, Deputy Secretary of Defense David Feinberg has requested that defense contractors ramp up production of key weapons systems, leading some to point out a signaling mismatch between Colby’s logic of resource constraints and the Pentagon’s actual procurement posture [2][6].

4. Key Issues

The first issue is the potential politicization of the reduction criteria. The inclusion of cooperation on specific foreign policy issues, such as the war with Iran, as a factor in selecting countries for troop cuts—going beyond the quantitative metric of defense spending—raises concerns that this could transform the alliance from a security partnership into a test of political loyalty [1][8].

The second issue is the potential gap between the review’s timeline and its actual implementation. The submission of options on November 6 is merely a preliminary step toward a final decision in December. As Foreign Policy notes, the political calculations of Congress, allied nations, and President Trump himself remain key variables that will determine the ultimate scale of implementation [10].

The third issue is the divergence in responses across Europe. While Eastern European countries are attempting to forestall reductions with the immediate offer of cost-sharing, Western European nations are continuing discussions at the level of “strategic autonomy” discourse, revealing a lack of uniformity in the pace and style of response within Europe [16][19][13]. This divergence is expected to become a test of alliance cohesion as NATO potentially transitions toward a dual-axis structure [9].

II. In-Depth Analysis

U.S. Review of Troop Realignment in Europe: An In-Depth Analysis

1. Analysis of Root Causes

The starting point for this review is fiscal. The U.S. defense budget has not expanded enough to allow for simultaneous responses in four theaters: the Indo-Pacific, the Middle East, the homeland, and Europe [6][7]. The Brookings Institution notes that the Trump administration’s National Defense Strategy begins with the premise that “the United States is at its limit, simultaneous threats are a reality, and the U.S. cannot bear all the burdens alone” [7]. This premise leads directly to a demand for reprioritizing troop deployments.

The second cause is the strategic shift to the Indo-Pacific, which designates China as the top-priority threat. Under Secretary of Defense for Policy Colby reiterated this same logic during a visit to the Philippines [2]. His consistent position is that troops and budgets currently committed to Europe must be reallocated to the Indo-Pacific. The review of the U.S. posture in Europe is just one component of this broader reprioritization, not a separate issue aimed solely at Europe.

The third cause is the Trump administration’s approach of measuring allied “loyalty” by criteria beyond defense spending. The JoongAng Ilbo reported that decisions on troop redeployments will incorporate the degree of guaranteed access to bases and airspace and the level of cooperation with U.S. foreign policy, such as on the war with Iran [1]. This approach goes beyond the quantitative metric of defense spending percentages to factor in an individual country’s diplomatic compliance. Citing Reuters, Tanzania’s The Citizen and Al-Monitor reported that concerns are spreading within NATO that countries deemed unsupportive of the U.S. during the Iran-Israel war could be subject to punitive reductions [8][12].

2. Structural Context

In terms of security architecture, this issue is a follow-up to the Trump administration’s decision in May to withdraw some U.S. military assets from the NATO Force Model and to step back from its role as the primary guarantor of Europe’s conventional defense [4]. The Brookings Institution assesses that this decision has “real consequences” for European NATO members [4]. This means the question of whether a Europeanized NATO can defend itself amid reduced U.S. support has already become a central theme in policy discourse [4].

In the political sphere, domestic checks and balances are at play within the United States. Foreign Policy has analyzed that the political interests of Congress, various European nations, and even President Trump himself could act as a brake on a rapid, large-scale withdrawal [10]. The outlet’s assessment is that troop redeployment is ultimately becoming a matter of internal military coordination over which units to maintain and which to withdraw [10]. This suggests a potential gap between Colby’s tough rhetoric and the actual scale of any reductions.

In the economic context, the preemptive response of Eastern European countries stands out. The Hungarian outlet HVG, citing Bloomberg, reported that Central and Eastern European NATO members planned to propose to Colby at the August 27 Brussels meeting that they would partially cover the operating costs of U.S. bases on their soil [16]. This bargaining chip, as highlighted by the Hungarian media, represents a pragmatic response that differs from the “strategic autonomy” discourse in major Western European capitals, as it targets base maintenance costs rather than an increase in overall defense spending. Telex reported that Romania is moving to shoulder more of the stationing costs to prevent further U.S. troop withdrawals [19]. For Eastern European countries bordering Russia, the physical presence of U.S. military assets is a far more urgent matter than defense spending percentages—a view commonly reflected in the region’s media.

3. Historical Precedents and Comparative Cases

Discussions about reducing U.S. troop levels in Europe are not new. The first Trump administration announced a reduction of U.S. forces in Germany in 2020, but the scope of that withdrawal was ultimately scaled back from the initial announcement due to congressional opposition and internal military resistance. In the current review, the political constraints identified by Foreign Policy—involving Congress, allied nations, and President Trump’s own calculations—are seen as potentially serving a similar buffering function [10].

However, the current review differs in nature from past instances. It represents a structural shift occurring within the documented strategic framework of the National Defense Strategy [6][7]. A pattern is also observable in which Colby’s message pressing for allied loyalty, which began in the Philippines, is first taking concrete shape in Europe before being sequentially applied to the Indo-Pacific [2][6]. A previous EAI analysis noted that “pressure in the form of an allied loyalty test, which started in Europe, is sequentially spreading to the Indo-Pacific” [6]. In other words, the realignment of U.S. troops in Europe is not a one-off event but a test case for new criteria that will be applied across the entire global alliance network.

4. Key Variables Shaping Future Developments

The first variable is the specific content of the four reduction options to be submitted on November 6. Multiple media outlets, citing the original Reuters report, have confirmed that this draft will be submitted to Secretary Hegseth ahead of the original December deadline [8][12][14]. The scope of these options will determine the level of security anxiety in Europe.

The second variable is whether the “loyalty test” is actually applied as a criterion for reductions. If the policy of factoring cooperation on the war with Iran into troop deployment decisions is implemented [1], NATO risks being transformed from a collective defense alliance into a set of bilateral, transactional relationships. This could act as a catalyst, expanding the debate on strategic autonomy from a focus of key Western European nations to the entire alliance.

The third variable is whether institutional brakes within the United States will actually function. The key question is whether the three factors identified by Foreign Policy—the political calculations of Congress, the military establishment, and President Trump himself—will act to moderate the scale of reductions, or whether the executive will of the Colby-Hegseth line will prevail [10].

The fourth variable is the diverging responses of Eastern and Western Europe. The future direction of realignment within NATO will depend on whether the Hungarian-Romanian model of offering to share base costs becomes widespread [16][19], or whether the concept of an integrated European self-defense, as discussed by Poland, France, and Germany, gains momentum [13].