Taking Stock of Northeast Asian Alliances
Editor’s Introduction: Hi there. In today’s Asia Policy Brief, Emma Chanlett-Avery, ASPI’s Director for Political-Security Affairs, assesses the last six months of the Trump administration and the impact it has had on U.S. allies Japan and South Korea. To add insult to injury, Secretary Rubio canceled his trip to Tokyo and Seoul this week, and President Trump recently announced the U.S. will impose 25% tariffs on goods from South Korea and Japan by August 1st.
State of Affairs: Six Months of Trump 2.0
A trio of international meetings revealed a grim outlook on Indo-Pacific alliances. The Shangri-La Dialogue, the G7, and the NATO summit provided little reason for optimism six months into the Trump administration. Supportive rhetoric aside, U.S. Defense Secretary Pete Hegseth previewed the escalating pressure for allies to surge their own defense spending at the Singapore forum. At the G7 gathering, President Donald Trump departed early, missing meetings with South Korean President Lee Jae Myung and Australian Prime Minister Anthony Albanese; a short meeting with Japanese Prime Minister Shigeru Ishiba showed a deep gulf on tariff negotiations. Even as the Transatlantic partnership appeared to retool its approach to U.S. demands, Japan, Korea, and Australia skipped the NATO meeting altogether, abandoning its previous commitments to attend and reassert the common interests between the West and Asian democracies. A fence-mending visit by U.S. Secretary of State Marco Rubio, scheduled for this month, was abruptly canceled, signaling more distress for the alliances. Just a few days before the 90-day pause on tariffs expired, Trump sent his first letters to Japan and South Korea announcing 25% tariff rate starting August 1 if deals favorable to him were not reached, shocking Seoul and Tokyo.
The question is whether the strain on alliances is temporary and can eventually recover, or if they will fracture beyond repair.
The Trump administration’s combination of imposing harsh tariffs and emphasizing burden-sharing has left Tokyo and Seoul reeling. Already under punishing tariffs, Japan and South Korea now face pressure to vastly elevate their own defense spending, straining their economies and leaving them smarting that allies are not treated differently than other countries. The common alarm that their security pacts with the United States are unraveling may have even driven closer ties between the two neighbors, who have traditionally had frosty relations under progressive governments in Seoul.
Why it Matters: Impact on Japan and South Korea
Japan’s early hopes at winning over President Trump turned out to be short-lived. A successful summit in the first month of Trump 2.0 boosted optimism that the alliance could sustain the momentum from gains made during the previous administration. A subsequent visit by Secretary Hegseth brought assurances of U.S. commitment to alliance modernization, albeit with a tone of aggressive language that made some Japanese uncomfortable—referring to Japan’s “warrior spirit” and stressing the need to build a “war-fighting base” in Japan. Then came the hammer of tariff impositions. With negotiations underway, the Pentagon has moved from general requests for more burden-sharing to specifying a 3.5-5% of GDP goal for defense spending from allies and partners—a threshold that Japan cannot muster for fiscal and political reasons.
Most striking is Japan’s withdrawal from plum opportunities to engage at the highest levels with the U.S. government: in addition to Prime Minister Ishiba’s abrupt reversal on attending the NATO summit, Tokyo has pulled out of a planned “2+2” meeting this summer, traditionally the platform for the U.S. Secretaries of State and Defense to meet with their counterparts and sign top-level agreements on security cooperation. Japanese leadership has traditionally been eager to pursue such openings, suggesting that Tokyo is reconsidering its strategic options more seriously than before. The question has always been how much Japan is willing to take on to keep the U.S.-Japan alliance intact and healthy. It appears that the tariff-slapped auto industry, coupled with Trump-specific disdain for alliances and the more general U.S. retrenchment from international leadership, may be the formula for Japan to say no more.
South Korea’s predicament overlaps with Japan’s, but Seoul may occupy an even less tenable position. South Korea had no chance to engage early with the second Trump administration due to a protracted political crisis caused by former President Yoon Suk Yeol’s impeachment. Newly elected President Lee Jae Myung arrived in office to face tariff rates similar to Japan’s, despite having a free trade agreement (FTA) with the United States. South Korea likely anticipates heavy pressure on burden-sharing given its past experience in President Trump’s first term, when the collapse of a cost-sharing agreement left an open wound in the alliance. South Korea spends roughly 2.3% of its GDP on defense, but that still falls well below the “gold standard” that the U.S. now expects. Without any opportunity to meet with President Trump directly at international meetings and without a bilateral summit scheduled, President Lee can only guess at how the U.S.-South Korea relationship will unfurl.
Beyond cost-sharing and tariff disputes, the U.S.-ROK alliance faces a more fundamental problem. The lifeblood of the alliance is based on DPRK policy coordination and the Combined Forces Command (CFC), with regular exercises and exchange between the U.S. and ROK militaries. President Trump threatens these lines: he has repeatedly threatened to pull U.S. troops off the Peninsula and prefers direct diplomacy with North Korean leader Kim Jong Un. These moves could sever military-to-military cooperation and marginalize Seoul. President Lee will have to navigate expectations from his progressive base on how to manage North Korea without setting an agenda so specific that it cannot withstand policy fluctuations from Washington.
U.S. alliance watchers have long been frustrated by the discord between Seoul and Tokyo when both face a common threat environment as China rises in the Indo-Pacific and the DPRK threatens each with nuclear destruction. Though it may not outweigh the costs, one benefit of adding U.S. pressure to the regional security and economic mix is that Korea and Japan appear to be prioritizing the immediate need to deal together with a changing Washington over the long-standing historical issues that have plagued more cooperation.
What to Watch: Paralysis or Progress?
How will Japan and Korea respond to Trump’s threat to raise tariffs on August 1? Can Tokyo or Seoul sell a new trade deal to their respective publics? And can U.S. allies trust that concessions made on trade will ease pressure on the security side?
Will Trump rejuvenate his personal diplomacy with Kim Jong Un and, if so, will he consult with Seoul? Can the progressive Lee—anxious to improve relations with Pyongyang—find a way to make a thaw in U.S.-DPRK relations work for his agenda?
Will the Japanese and Korean domestic publics sustain support for their leaders to put aside history-related disagreements and forge a cooperative relationship? Early indications are positive, with a productive and warm bilateral meeting on the sidelines of the G7.
After the Upper House elections in Japan this summer, will Ishiba survive as Prime Minister? Would a new leader take a different tact with Washington, either standing up to demands for more defense spending or acquiescing in a bid to curry Trump’s favor?
Dive Deeper with ASPI
Register to attend ASPI’s upcoming event in New York on July 22: “The U.S.-ROK Alliance in 2025 and Global Implications,” with welcome remarks by Asia Society President & CEO Dr. Kyung-wha Kang and featuring former officials and senior experts from Washington and Seoul.
Watch Emma Chanlett-Avery moderate an expert panel on “Political Reset? Implications of the ROK Election for the Alliance and the Region.”
Read Emma Whitmyer’s latest analysis for ASPI’s Ballot Box on “South Korea’s 2025 Presidential Election: Navigating Economic and Security Challenges amid Divisions.”
Read Emma Chanlett-Avery’s op-ed for the South China Morning Post, “Will Trump’s Economic Tsunami Undermine the U.S.-Japan Security Partnership?”