On Monday, US President Donald Trump welcomed South Korean President Lee Jae-myung to the White House. That Trump’s welcome would be warm was very much in doubt, as shortly before the meeting the US president posted on social media “WHAT IS GOING ON IN SOUTH KOREA?” But when the two leaders sat down together, there was no sign of contention—and several signs of what to expect substantively for the US-South Korea alliance going forward. Below, Atlantic Council experts answer five pressing questions about what the two leaders discussed, from US forces in Korea to Korean-aided US shipbuilding stateside.
1. What did this meeting tell us about the future of the US-South Korean relationship?
Overall, the public comments in the Oval Office and what is known so far of the private discussions suggest that fears of a break in the relationship were overblown. In fact, it appears that a new approach for the alliance is already taking shape under these two leaders.
Sensitive issues raised by journalists in the Oval Office press availability that could easily have derailed the conversation—or at least been perceived as key sticking points—were deflected effectively by the two leaders. For example, Trump demurred when asked about cutting back US Forces Korea (USFK), and though he held firm on the need for greater cost-sharing for the US military presence there, Lee did not contest the point. Far from showing differences on their approaches to China—one topic where many commentators expected a disconnect—the leaders joked about traveling together to meet Chinese President Xi Jinping. How these topics were handled with reporters does not mean, for example, that finding agreement on the future shape of USFK or on an alliance posture toward China will necessarily be easy. But it does suggest that these thorny issues will not be as bitterly contentious as some might have thought.
Several potential themes for enhanced alliance alignment also emerged from the meeting. Defense industrial cooperation—in particular, working together on shipbuilding—is clearly becoming a primary focus of the alliance. Lee and Trump also seem to share the view that North Korea’s development of its nuclear and missile capabilities has led to a deterioration of the security situation on the peninsula. At the same time, Lee’s deference to Trump on North Korea issues—with Lee referring to himself as a “pacemaker” following Trump’s lead as “peacemaker” was noteworthy. Despite the clear desire of Lee and his supporters to reduce South Korea’s reliance on the United States for its security, Lee appears comfortable with continued US leadership on the approach to North Korea and he may be signaling that Seoul will not seek to get out ahead of Washington on North Korea diplomacy.
—Markus Garlauskas is the director of the Indo-Pacific Security Initiative of the Scowcroft Center for Strategy and Security.
2. What did Trump’s comments indicate about the future of US force posture in South Korea?
The Trump-Lee summit was widely anticipated as a watershed moment for the US-South Korea alliance. Expectations centered on contentious issues: the potential reduction of USFK, the expansion of strategic flexibility, and the long-pending transfer of wartime operational control, all under the rubric of “alliance modernization.” Yet the meeting ended with less clarity on these issues than ambiguity. Trump emphasized his “very good relationship” with Kim Jong Un, and he expressed interest in another summit with the North Korean leader later this year. This announcement overshadowed the hard-security deliberations and left allies wondering what direction Washington truly intends to pursue.
For Seoul, this uncertainty carries both risks and opportunities. On one hand, any discussion of USFK drawdowns stirs concerns that Pyongyang could interpret the move as weakening deterrence. On the other hand, alliance modernization could yield a more adaptive posture if framed around enhanced capabilities—such as advanced airpower, missile defense, and unmanned systems—rather than troop numbers alone.
The summit provided no concrete answers to important questions about what’s next for USFK, leaving Seoul to push for assurances that US capabilities will remain firmly committed to the peninsula. The question of strategic flexibility similarly remains unresolved. While Washington seeks freedom to redeploy forces for contingencies beyond Korea, Seoul fears becoming entrapped amid intensifying US-China competition. Anxieties in South Korea are likely to continue after the summit due to the absence of specific commitments during the meeting. The issue of operational control, too, appears to remain unsettled.
In the end, the Lee–Trump summit highlighted the gravity of alliance transformation but left more questions than answers. The task now is to ensure that ambiguity does not devolve into drift, but instead becomes an opening for deliberate, sustained dialogue to shape a stronger, more credible alliance.
—Bee Yun Jo, PhD, is a nonresident senior fellow at the Indo-Pacific Security Initiative at the Atlantic Council’s Scowcroft Center for Strategy and Security and research fellow in the Security Strategy Division at the Sejong Institute.
3. Both leaders showed a willingness to meet with North Korean leader Kim Jong Un. What could come out of that?
The leaders’ willingness to meet with Kim is very much in line with what both of them had expressed separately before the summit. Some of their comments suggested that they may be setting the stage for a coordinated approach toward diplomacy with North Korea, which is important to ensure solidarity and avoid seams that Pyongyang or Beijing could exploit.
Not much may come of this willingness and coordination, however, because of the North Korean leader’s belligerence, intransigence, and stubborn refusal to give up his nuclear-weapons program. Kim Yo Jong, Kim Jong Un’s sister and top international spokesperson, recently underscored that Pyongyang must be accepted by Washington as a nuclear weapons power, and she scoffed at the Lee administration’s attempts to reach out. Given that Trump reemphasized denuclearization as his goal for diplomacy with North Korea, and that he praised Lee’s approach to the North—even as he emphasized his positive relationship with Kim Jong Un—his comments could be seen by Pyongyang as a direct, if polite, rebuff to Kim Yo Jong’s recent statements.
Whether or not Kim takes them up on their offer to engage, Lee and Trump showing a clear willingness to meet helps put the onus back on the North Korean leader for the diplomatic impasse, helping to underscore to Beijing and other critics that it is not a lack of willingness on the part of the United States that is the roadblock to dialogue.
—Markus Garlauskas
4. What progress was made on US-South Korean trade, and shipbuilding in particular?
On trade issues broadly, both leaders expressed satisfaction. The summit reaffirmed the framework announced in July, which set US tariffs on South Korean goods at 15 percent. Trump noted that the Korean side had raised concerns prior to the meeting but emphasized that the deal would be finalized without changes.
Most notably, the meeting elevated shipbuilding to the top of the agenda. Trump said: “In World War II, the US built one ship a day, but now the US shipyard is quite devastated,” stressing the need to revive US shipbuilding. The July framework already included South Korea’s $150 billion pledge to rebuild US shipyard capacity with Korean expertise. At the summit, Trump went further, signaling possible coproduction: Korean firms building ships at American yards with US labor.
South Korea, for its part, deliberately spotlighted shipbuilding as the centerpiece of cooperation. Lee even visited Hanwha’s Philadelphia shipyard to underscore the commitment. Lee branded the initiative with the slogan “Make American Shipbuilding Great Again (MASGA),” cleverly echoing Trump’s own rhetoric. In effect, the phrase could also be read as “Make America and South Korea Great Again,” reinforcing the broader alliance narrative.
Yet significant challenges remain before this partnership can be fully realized. Legally, any coproduction at US shipyards must comply with domestic laws, such as the Buy American Act and the Jones Act, raising questions about how to implement cooperation without delays or disputes. Geopolitically, China is watching closely. Beijing’s state media has already warned that if South Korean shipbuilding products are used in US military operations, Seoul could face serious consequences.
Thus, while the Trump–Lee summit produced visible progress on trade and shipbuilding, success will depend on navigating legal barriers and geopolitical pressures.
—Sungmin Cho is a nonresident senior fellow in the Indo-Pacific Security Initiative at the Atlantic Council’s Scowcroft Center for Strategy and Security.
5. What signals did the leaders send about the future of the US-South Korea-Japan trilateral cooperation?
Ahead of the US-South Korea presidential summit, Lee seemed determined to fulfil his campaign promise to broker new diplomatic opportunities through a pragmatic foreign policy, particularly on inter-Korea relations. Diplomacy is important, though security must come first. Any effort by Lee to advance renewed North-South Korean relations will likely hinge on reinforcing South Korea’s bilateral and multilateral partnerships with the United States and Japan.
Lee has repeatedly called Japan an “important partner” for cooperation and declared his aims to solidify US-South Korea-Japan trilateral cooperation in the Indo-Pacific region. Even during his National Liberation Day address—a yearly commemoration of South Korea’s liberation in 1945 from Japanese occupation—Lee balanced historical remembrance alongside the importance of seeking forward-looking relations with Japan.
Breaking with a six-decade tradition, Lee’s first bilateral visit was not to Washington but to Tokyo—a move designed to signal Lee’s intent to restart and bolster trilateral US-South Korea-Japan relations. Meeting with Japanese Prime Minister Shigeru Ishiba only days before his summit with Trump, Lee declared the swift resumption of South Korea-Japan shuttle diplomacy and reaffirmed both nations’ commitments toward North Korea and the “complete denuclearization and permanent peace on the Korean Peninsula.”
Interestingly, Trump may be Lee’s biggest ally in promoting renewed North-South Korean relations. During the presidential summit, Trump heavily emphasized his interest in meeting with the North Korean leader—presenting historical parallels to US-South Korean relations during Trump’s first term. However, it remains to be seen how these early overtures from Washington and Seoul will be perceived in Pyongyang.
As the Trump-Lee partnership moves forward, they must not forget a core lesson from past North Korea strategies: Engagement cannot come at the expense of maintaining strong, credible US-South Korea deterrence and joint military readiness in the region. Lee’s post-summit pledge to increase defense spending and technical cooperation underscores his commitment to modernizing the US–South Korea alliance and strengthening joint strategies against rising threats in the Indo-Pacific.
As Lee and Trump navigate a complex diplomatic landscape, their ability to balance engagement with credible deterrence will define the next chapter of security and stability on the Korean Peninsula. If managed wisely, the renewed momentum in US-South Korea-Japan trilateral cooperation could offer a rare window for pragmatic progress in inter-Korean relations—without compromising regional security.
—Kayla T. Orta is a nonresident fellow in the Indo-Pacific Security Initiative at the Atlantic Council’s Scowcroft Center for Strategy and Security.
***
All eyes were on the Lee-Trump Summit as the US president publicly called out the South Korean government mere hours before the two presidents were scheduled to meet. Many were unsure of the reception Lee would receive due to concerns regarding trade deals, USFK posture, and more. But Lee’s charm and pragmatic diplomacy had a strong effect, and both presidents seemed pleased with the initial outcomes.
A major question still lingers, however, on the future of US-South Korea-Japan trilateral cooperation under the new kaleidoscope of leaders.
Days before the White House summit, Lee visited Tokyo to meet with Ishiba. Making Japan his first trip abroad in office was a first for any Korean president, and it was a strong statement of his willingness to “seek forward-looking, mutually beneficial cooperation with Japan.” Following this summit in Tokyo, both leaders committed to work together with the United States for the “complete denuclearization of North Korea.” This statement, in conjunction with Trump expressing his desire to speak with the North Korean leader, with Lee’s encouragement, shows early signs of continued support for trilateral cooperation in the security realm.
While these signs are undoubtedly encouraging, time will tell how this momentum will hold up to forthcoming conversations on the USFK posture and burden-sharing, an apparent mismatch of expectations for how to engage with Beijing, and Ishiba’s uncertain future following the Liberal Democratic Party’s recent election troubles.
—Lauren D. Gilbert is a deputy director with the Atlantic Council’s Indo-Pacific Security Initiative housed within the Scowcroft Center for Strategy and Security.
Further reading
Tue, Jun 24, 2025
The ‘ironclad’ US-South Korea alliance is outdated. A new age requires a ‘titanium’ alliance.
New Atlanticist By Markus Garlauskas
Washington and Seoul must set a new foundation for the seventy-year-old alliance that reflects the current strategic environment.
Thu, Jul 10, 2025
South Korea is the ideal anchor for the first island chain
Issue Brief By Brian Kerg
The assumptions underpinning analysis and discussion of conflict in the Indo-Pacific are due for a rethink. Though many conversations about Chinese military aggression assume South Korea would not get involved, it could play a decisive role in deterring and defeating an attack on Taiwan.
Tue, Jun 3, 2025
Experts react: What does South Korean President Lee Jae-myung mean for Indo-Pacific security?
New Atlanticist By
Democratic Party candidate Lee Jae-myung has been elected as South Korea’s next president. Atlantic Council experts delve into what his administration could mean for Indo-Pacific security and more.
Image: US President Donald Trump welcomes South Korean President Lee Jae Myung at the White House in Washington, D.C., U.S., August 25, 2025. REUTERS/Brian Snyder
