Expected Changes to U.S. Korean Peninsula Policy if Trump is Reelected and Potential Response Strategies

Sungwon Lee

Research Fellow

Peter Ward

Research Fellow 

1. Introduction

   The 2024 U.S. presidential race has unfolded dramatically, and with just over a month remaining until the election, the outcome remains difficult to predict. Amid deepening partisan divisions among voters, if Trump continues to rally his base and attract so-called “shy Trump“ voters and undecided voters, the possibility of his reelection cannot be dismissed.

   Trump's reelection is expected to bring about widespread changes in U.S. foreign policy, significantly impacting East Asia and the Korean Peninsula. During his first term, Trump's foreign policy was characterized by “transactionalism” and his “America First” approach, which prioritizes U.S. fiscal and strategic interests from a cost-benefit perspective, along with a shift from internationalism to economic nationalism. This America First foreign policy direction will likely persist if Trump returns to office.

   A second Trump administration is likely to have a multifaceted impact on East Asia. In particular, policy changes surrounding alliances, China, and North Korea could directly affect South Korea. On alliance policy, burden-sharing - both in terms of costs and responsibilities - is likely to be a central theme, and U.S. allies will likely face increased burden-sharing pressure regarding the scale, role, and costs of U.S. troops stationed in their countries.

   Trump and his close advisors have repeatedly raised concerns about the “imbalance” in the U.S.-ROK alliance, demanding higher defense contributions for U.S. forces in Korea, and even suggesting the possibility of reducing or withdrawing U.S. troops. China Policy: The Trump camp perceives China as a comprehensive threat and maintains a high level of threat awareness. An East Asia security policy focused on containing China is expected to have a substantial impact on both regional stability and security on the Korean peninsula.

   On North Korea Policy, if Trump is reelected, the unconventional approach with North Korea he attempted during his first term may resume. However, the risk of South Korea’s national interests being sidelined throughout the course of engagement and negotiations between North Korea and the U.S. (referred to as “Korea passing”) is a concern that cannot be ignored. Given the lack of incentives for North Korea to return to negotiations, it is expected to be difficult to bring Pyongyang back to the table under the same conditions as before.

   As a result, negotiations could take the form of arms control talks that acknowledge North Korea’s nuclear capabilities, which would severely undermine the U.S.-ROK alliance and regional stability. In fact, some experts predict that in exchange for easing sanctions, an agreement may be reached for North Korea to freeze, rather than completely dismantle, its nuclear program and pause the development of new weapons systems. Concerns over the so-called U.S. abandonment of South Korea are growing, with some figures from the first Trump administration even discussing freezing North Korea’s nuclear program and reducing the number of U.S. troops in Korea.

2. Expectations for Alliance Policy if Trump is Reelected

   If reelected, Trump’s alliance policy is expected to focus largely on military burden-sharing with allies, emphasizing allies’ financial responsibilities, reassessing alliance structures (that provide unilateral benefits), and strengthening strategic cooperation with allies to maintain influence in Asia. Trump’s “America First” approach and focus on “tangible benefits” reflect his tendency to approach alliance relationships from a cost-benefit perspective. While the Republican Party platform emphasizes “peace through strength” backed by strong military power, Trump’s approach is expected to remain defensive, aiming to minimize unnecessary military interventions that do not align with U.S. interests.

   If reelected, a second Trump administration will likely demand increased defense cost-sharing from NATO and Asian allies. For example, Trump perceives increased defense contributions and troop withdrawals from rich allies as means to prevent unfair outflow of funds. Trump emphasizes ending unilateral U.S. support for allies and insists that allies assume responsibility for their own defense.

   In his approach to alliances, a second Trump administration is likely to favor practical tools for achieving mutual benefits, unconstrained by tradition or values. This approach may involve reassessing alliances based on whether they contribute substantively to U.S. security and require increased demands for responsibility and cost-sharing from allies if they do not meet these criteria.

   Furthermore, even if Trump is reelected, the overall policy direction of maintaining influence in Asia and strengthening alliances to contain China is expected to persist. The prevalent view is that a second Trump administration would maintain an adversarial stance, defining China not merely as a competitor but as a comprehensive threat, alongside continued strong countermeasures. There is broad bipartisan agreement on the importance of Asian alliances and partnerships in countering China, and securing a dominant position in the region is likely to remain a cornerstone of U.S. foreign policy. The Indo-Pacific region continues to be widely viewed as a strategic focal point closely tied to core U.S. economic and security interests. The justification and need for strengthening strategic cooperation with allies to contain China’s military expansion in Asia are likely to persist. Therefore, it is expected that Japan, South Korea, the Philippines, and Taiwan, among other geopolitically important allies and partners, will continue to be recognized as playing essential roles in maintaining the U.S. line of defense.

3. Potential Impact and Concerns for the Korean Peninsula if Trump is Reelected

A. Expectations for North Korea Policy if Trump is Reelected and Associated Concerns

   The current U.S. administration’s policy stance toward North Korea involves pressuring the regime through a combined strategy of maintaining denuclearization efforts, sanctions, and diplomatic dialogue. The administration has pursued a policy that retains channels for dialogue while utilizing diplomatic pressure and economic sanctions. This approach has emphasized close cooperation with allies to manage the North Korean threat and has favored a more traditional, multilateral strategy. President Biden has stressed maintaining an approach to the North Korean issue that utilizes cooperation with allies, including South Korea, and the importance of the united resolve and solidarity of the international community to achieve denuclearization.

   In contrast, Trump could potentially bypass traditional diplomatic channels to restart unconventional diplomacy with North Korea, including high-profile U.S.-North Korea summits that can capture global attention. After the Hanoi Summit, there is widespread domestic and international consensus that North Korea is unlikely to respond to a similar proposal. However, the possibility that Trump might offer an unconventional new proposal to resume talks cannot be completely ruled out.

   As shown in Table 4, Trump’s advisors have expressed diverse views on addressing the North Korean nuclear issue.

Table 1. Key Republican Figures’ Views on Approaches to the North Korean Nuclear Issue

   Based on these arguments, continuity in denuclearization policy appears likely. However, given the deadlock in resolving the North Korean nuclear issue, a second Trump administration, recognizing the limitations of sanctions, may consider resuming negotiations with North Korea through sanctions relief and arms control talks. There is a possibility that the U.S. may tacitly recognize North Korea’s nuclear capabilities and initiate arms control negotiations, provoking strong opposition from traditional U.S. allies. This approach raises concerns as it could significantly alter regional security dynamics and alliance relations. If Trump attempts to deal directly with North Korea, there is a risk that South Korea’s security interests may be sidelined.

B. Potential Approach to the ROK-U.S. Alliance if Trump is Reelected and Associated Concerns

   If Trump is reelected, it could reignite tensions between South Korea and the U.S. over the presence of U.S. forces in Korea. Trump has been highly critical of alliances, even in Europe, where he announced plans to reduce the number of U.S. troops stationed in Germany from 35,000 to 25,000 during his first term. It has also been reported that following his 2020 election loss, Trump considered a complete withdrawal of U.S. troops from Germany. In his 2024 campaign, Trump promised to assist NATO member countries facing Russian aggression if they spent 2% or more of their GDP on defense, but he has expressed his intention to take a passive approach toward allies not meeting this threshold.

   When it comes to the ROK-U.S. alliance, Trump has been consistently critical of the role of the alliance, the scale of defense spending, and the issue of burden-sharing. During his previous term, he frequently raised objections regarding the share of defense costs for U.S. Forces in Korea (USFK). In an interview with TIME, Trump once again called for an increase in defense spending, describing South Korea as a “wealthy country.” In addition, while claiming that the Biden administration lowered the South Korean government’s defense costs, Trump also expressed inconsistent views on the ROK-U.S. defense cost-sharing negotiation process. There are conflicting expectations and opinions among key figures when it comes to increasing South Korea’s defense contributions and adjusting the size and role of U.S. forces in Korea.

Table 2. Key Figures’ Positions on Increasing Defense Contributions and the Scale and Role of USFK

   To summarize current discussions on North Korea policy, the U.S. appears likely to pursue both deterrence of North Korea and containment of China in the Indo-Pacific region through transactional and pragmatic approaches. The role of USFK may be expanded and adjusted to keep increased North Korea-Russia cooperation in check as well as contain China’s expansion. Considering the limitations of the non-proliferation policy, the possibility of South Korea strengthening its own defense capabilities (including the potential for nuclear armament) to address the North Korean nuclear issue cannot be ruled out.

   In addition, there is a possibility of a shift in the role of military cooperation between allies with the belief that the responsibility for Asia’s security should be transferred from the United States to its allies in the region. In fact, the U.S. Congress will and role in maintaining U.S. forces in South Korea will be crucial as it represents the most effective institutional check on the president’s authority regarding USFK presence.

   Stable alliance management requires bipartisan support for maintaining U.S. troops in Korea. The National Defense Authorization Act (NDAA) for Fiscal Year 2018 restricted the president’s ability to reduce the number of U.S. troops stationed in Korea below a certain threshold without approval congressional approval. The NDAA for Fiscal Year 2025, which was recently passed by the U.S. House of Representatives, is also reported to include provisions to maintain the number of U.S. troops at 28,500 personnel.

   However, if reelected, Trump may still bypass various institutional checks to make unilateral decisions. If Republicans who support Trump secure a majority in Congress, the legal risks associated with unilateral decision making could be reduced, so now is the time to discuss response strategies.

C. Expectations for Persistence of the NCG and Camp David Initiatives if Trump is Reelected

   An integrated deterrence approach combining strategic, conventional, and unconventional military capabilities, along with close cooperation with allies, remains essential for addressing the evolving threats in the region. Given the bipartisan consensus on containing China, there is a strong likelihood that the U.S. approach to Asia will maintain overall continuity even if Trump is reelected. Trump is expected to remain hostile toward China, which aligns with broader U.S. strategic priorities.

   If Trump is reelected, enhanced cooperation between allies, intelligence sharing, and joint military exercises may be required to strengthen military readiness. From this perspective, there is growing optimism among U.S. experts that Korea-U.S.-Japan trilateral cooperation, which was developed through the Camp David Summit, will persist regardless of the outcome of the presidential election. Considering the macro-level security interests in East Asia, we are likely to see the continuation of U.S. extended deterrence commitments, which have been reinforced through the Washington Declaration and the Nuclear Consultative Group (NCG).

   However, a noteworthy opposing opinion suggests that Trump’s preference for bilateral transactional diplomacy could potentially weaken the momentum of trilateral cooperation among the U.S., South Korea, and Japan. Some of Trump’s close advisors have mentioned the possibility of pulling out of previous agreements, arguing that American cities should not have to endure the threat of nuclear attack to defend Seoul. Despite institutionalized deterrence measures like the Nuclear Consultative Group (NCG), there remains a risk due to the U.S. president's sole authority to decide on nuclear weapons use.

   Another anticipated shift in terms of security policy is a possible transition from a values-based alliance to a more military-centric alliance. For instance, Elbridge A. Colby, former deputy assistant secretary of defense for strategy and force development, stated that “it’s not a matter of how much you enjoy American music; it’s an issue of how much South Korea contributes (as an ally),“ emphasizing the need for security policies that prioritize the strength and role of the military over fondness.

   In summary, if Trump is reelected, there is a high likelihood of continuity in the commitments made by the U.S.-South Korea Nuclear Consultative Group and U.S.-ROK-Japan trilateral cooperation to contain China and maintain extended deterrence. An expanded role for USFK, as well as enhanced military cooperation, intelligence sharing, and joint exercises among allies, are expected. The nature of the alliance is expected to shift from values-oriented to a focus on the contributions and roles of the military.