U.S. President-elect Donald Trump sparked significant controversy during his press conference at the Mar-a-Lago resort in Florida on December 16, 2024. The controversy stemmed from Trump's exclusion of South Korea from the list of nations with which he plans to enhance cooperation or alliances in the coming period. Set to assume office on January 20, 2025, Trump expressed his intent to meet with North Korean leader Kim Jong-un, Chinese President Xi Jinping, Russian President Vladimir Putin, Ukrainian President Volodymyr Zelenskyy, and Japanese Prime Minister Shigeru Ishiba. Notably absent from his statement was any mention of his relationship with the leaders of South Korea—one of Washington's most critical and long-standing allies in Asia.

Trump's disregard for South Korea has raised concerns among observers and analysts of South Korean affairs about the future of the long-standing security and strategic alliance between Seoul and Washington, a cornerstone of peace and stability on the Korean Peninsula. These concerns have emerged amid a significant political crisis unfolding in Seoul, following the National Assembly's decision to impeach President Yoon Suk-yeol on December 14. The impeachment was a response to Yoon's short-lived attempt to impose martial law on December 3.

According to the constitution, the Constitutional Court of Korea now has six months to review the case and determine whether President Yoon will be removed from office or reinstated. Washington appears to have been caught off guard by Yoon's decision to declare martial law and suspend the constitution. Judging from public statements by senior American officials, Yoon seemingly did not inform the U.S. in advance, despite the significant strengthening of security and military alliance relations between the two countries since he took office on May 12, 2022, to address the evolving nuclear and missile threats posed by North Korea.

Adding to the tension, South Korea's Foreign Minister, Cho Tae-yul, has faced sharp criticism from the U.S. in recent days for avoiding phone calls from the U.S. Ambassador to Seoul, Philip Goldberg, on the night martial law was declared in the country.

Despite assurances from the foreign ministers of South Korea and the United States on December 21, 2024, regarding their commitment to maintaining a strong alliance, the ongoing political crisis in Seoul, culminating in President Yoon's impeachment, is likely to negatively impact the future of the security and strategic partnership between the two nations. Prime Minister Han Duck-soo, who served as South Korea's Ambassador to the United States from 2009 to 2012, assumed the role of acting president immediately after the National Assembly's impeachment vote. However, the situation remains precarious, especially considering President Trump's recent oversight of South Korea in his latest press conference.

Several key considerations support this assessment, the most important of which can be outlined as follows:

1- US Aggressive Economic and Military Policies:

The Trump administration is likely to impose its own terms and conditions on Seoul regarding trade, defense, and security issues. Under the principle of "America First," the second Trump administration is expected to pursue aggressive economic policies against countries with which the United States has a significant trade deficit, including South Korea. Potential measures by the US in this regard encompass imposing tariffs on South Korean exports such as semiconductors, automobiles, and batteries, reducing support, and renegotiating the Free Trade Agreement (FTA) between the United States and South Korea, which was signed on June 30, 2007.

Militarily, President Trump is expected to urge South Korea and other allies to increase their defense spending and take on greater responsibility for their own security. Observers anticipate that the U.S. president will likely ask South Koreans to renegotiate a new cost-sharing agreement for defense. In October 2024, Seoul and Washington concluded their twelfth military agreement, determining South Korea's share of the costs for stationing 28,500 U.S. troops in the country. The agreement, set to last until 2030, stipulated that Seoul would pay 1.52 trillion won (approximately $1.04 billion) in 2026, up from 1.4 trillion won (approximately $957 million) in 2025.

During his election campaign, President Trump stated that South Korea would pay $10 billion annually for the stationing of U.S. troops in its territory if he were to return to the White House. He also described the Asian ally as a "money machine," according to South Korea's Yonhap News Agency. Trump's stance toward South Korea aligns with his broader statements and policies urging allies to increase their military spending, a position that has recently come to the forefront. For instance, Trump's team reportedly informed European officials that he would demand NATO member states raise their defense spending to 5% of their GDP, according to the Financial Times.

2- Engaging with North Korea and China:

President Trump repeatedly expressed his willingness to engage with North Korea and China during his election campaigns, acknowledging that both nations pose significant security threats to South Korea. He even suggested holding a new summit with North Korean leader Kim Jong-un, describing him as a leader with whom he gets along very well. Previously, Trump had met with Kim twice—in Singapore in 2018 and Hanoi in 2019—to discuss halting Pyongyang's nuclear and missile programs. Despite these efforts, the summits failed to achieve any breakthrough in this regard.

3- Potential Sidelining:

South Korea risks being relatively sidelined in favor of other partners in East Asia, particularly Japan. During a recent press conference, Trump completely overlooked South Korea while announcing a major investment deal with Masayoshi Son, CEO of Japan's SoftBank Group. The deal plans to invest $100 billion in U.S. projects over the next four years, creating 100,000 jobs.

Furthermore, Trump and his wife hosted a private dinner for the widow of the late Japanese Prime Minister Shinzo Abe, whom Trump previously referred to as a "soulmate." According to the Japanese Mainichi Shimbun newspaper, the dinner marked Trump's first meeting with a Japanese public figure since his election victory on November 5.

Trump also hinted at the possibility of meeting with Japanese Prime Minister Shigeru Ishiba before his official inauguration in January. These actions reflect the new U.S. administration's apparent inclination to favor Japan over South Korea in its efforts to shape security, strategic, and economic alliances in East Asia.

In any case, the coming months are likely to represent a critical juncture for the security and strategic alliance between South Korea and the United States. Escalating economic, military, and diplomatic repercussions stem from the parliament's decision to impeach the president. A key factor is the possibility of opposition Democratic Party leader Lee Jae-myung being elected as South Korea's new president. Lee advocates for balanced and independent relations with Washington and a more conciliatory approach toward North Korea, contrasting with President Yoon's preference for strengthening the alliance with the U.S. and taking a confrontational stance toward Pyongyang.

Moreover, the future of the Seoul-Washington alliance is likely to become even more complicated with President Trump's return to the White House this month. Trump's policies toward Seoul could deliver a significant blow to this alliance, particularly if he pursues closer ties with North Korea, insists on renegotiating trade agreements, demands South Korea pay $10 billion annually for the U.S. security and military umbrella, or pressures them to increase purchases of American weapons.

The potential decline in the security and strategic alliance between Seoul and Washington under Trump's second administration is likely to increase the chances of chaos and instability on the Korean Peninsula. Such a shift could create a significant gap in the United States' strategy, and possibly even in NATO's strategy, in the Indo-Pacific region. The situation is especially concerning given the growing military cooperation between North Korea and Russia, Pyongyang's continued development of its nuclear and missile programs, and China's ongoing military and economic rise in the region.