On August 16, U.S. President Donald Trump scaled back military drills with South Korea. In a social media post, he cited three different explanations for the move: the cost of the exercises to the United States, his supposedly friendly relations with North Korean leader Kim Jong Un, and his displeasure over perceived lack of South Korean support for the U.S. war effort against Iran. 

After Trump’s intervention, the annual Ulchi Freedom Shield exercise, which started on August 17, only ran through August 21 instead of the originally scheduled August 27. In practice, the first phase of the exercise – focused on defense – was preserved while the second phase – focused on counterattack – was canceled. In addition, live-training exercises were replaced with simulations. 

According to the South Korean new agency Yonhap, South Korean Foreign Minister Cho Hyun told the legislature that “Neither our government nor U.S. officials knew what President Trump wrote on his Truth Social account.” In a meeting with the National Assembly Committee on Foreign Affairs and Unification, Cho said, “We were not notified in advance.”

On August 24, the United States canceled the biennial Ssangyong drills, a large joint amphibious landing exercise, scheduled for September. This time, the justification was constraints on force availability caused by the Iran war. This announcement was not as abrupt, as the U.S. Marine Corps had officially notified Seoul back in June that its force availability would likely be constrained. 

On August 28, the United States, South Korea, and Japan announced that they will conduct the annual Freedom Edge drills, joint military drills to test readiness against North Korea’s missiles and nuclear weapons threat, from September 9 to 11. 

What is Japan’s perspective on the latest developments in the South Korea-U.S. alliance? 

Japan’s initial reaction has been muted. Japanese Defense Minister Koizumi Shinjiro responded to the announcement by saying: “As Japan faces the most severe and complicated security environment in the post-war era, the cooperation among Japan, the United States, and South Korea is critical to the peace and stability of the region.” The statement, however, did not actually criticize the U.S. decision to scale back joint exercises.

Although Japanese leaders have been publicly quiet, this incident highlights several points of concern that have existed since the second Trump administration.  

First, it could indicate a more aggressive move by Washington to resume talks with North Korea. Japan would always have been wary of a North Korea-U.S. deal that advanced U.S. security while sidelining Japanese concerns. For example, a hypothetical deal could cut back on Pyongyang’s long-range missiles, which can reach the United States, but do nothing to reduce its stockpile of short-range missiles, which can reach Japan. The threat to Japan remains persistent, as North Korea fired 10 short-range ballistic missiles on August 20; this was the third ballistic missile test in August. 

There is also a question of whether the United States will maintain denuclearization as a policy objective, and what Japan will do vis-à-vis North Korea if the United States abandons it. Conservative Japanese leaders also have a vested political interest in the return of abductees, an issue that might get ignored in a North Korea-U.S. deal. 

Japanese analysts worry about a more emboldened North Korea, though at the same time they doubt the likelihood of a U.S. overture to Pyongyang succeeding. But experts have failed to predict many aspects of this administration’s foreign policy. 

U.S. overtures to North Korea, reciprocated or not, will likely be reflected in the three strategy documents currently being revised in Tokyo: the National Security Strategy, the National Defense Strategy, and the Defense Buildup Program. Japan intends to finish updating these documents by the end of the year. Tokyo could also, much more quietly, consider nuclear weapons for itself if questions about the credibility of the U.S. nuclear deterrent being to mount. 

Another worrying aspect of Trump’s social media post is the signal that the United States is prepared to more explicitly make assistance in the Iran War a condition of continued support. Certainly, there are different dynamics between the South Korea-U.S. alliance and that between Japan and the United States. For one, Japan has long relied on its constitutional and legal framework to avoid entanglement in U.S. wars. However, the Trump administration may be less sympathetic to such justifications. If they cannot force Japan to support U.S. military operations in the Strait of Hormuz due to Japan’s constraints, Washington may demand concessions from Japan in other areas, such as reduced joint exercises or increased host nation support. 

This administration has shown a tendency to link security and economic issues in a way that previous administrations usually did not (i.e., reducing the benefit of the training exercise to its financial costs). The timing is particularly worrying for Japan as Tokyo begins negotiations with Washington over host nation support. A sudden demand for a large increase is certainly possible. 

Trump’s decision – announced on the same day Ulchi Freedom Shield began – makes it clear that U.S. military exercises can be scaled down on a moment’s notice. Japan has its own exercises with the United States, Keen Sword, in October. Though it is expected to be smaller than the 2024 iteration due to U.S. deployments in the Iran war, it could be scaled back even farther. Trump could use the same three-fold justification he used against South Korea to cancel or scale down these exercises. 

In a related concern, Trump’s rationale for the decision showed his susceptibility to accepting autocrats’ talking points. Trump appears to have bought Kim’s argument that the training exercises are aggressive, while the U.S. and South Korean governments have long maintained that these exercises are defensive. It’s odd, to say the least, to see a U.S. president describing actions by the South Korea-U.S. alliance as “totally inappropriate and hostile” and North Korea as “unthreatening and respectful.”

Finally, there is real concern about what it would mean for U.S military readiness on the Korean Peninsula and in the Indo-Pacific more broadly if training exercises become scaled back or more erratic.

Alliance readiness is a key concern. While North Korean soldiers are returning to the peninsula after having real world battle experience in the Russia-Ukraine war, the best that the U.S. and South Korean soldiers can do to prepare is live trainings. Yet these live trainings are being replaced by simulations at the same time the enemy is “training” by engaging in real combat. 

A U.S. Department of Defense official said in a statement that “These adjustments preserve essential readiness and training objectives,” and “There will be no degradation to U.S. training objectives.” But saying the sky is pink does not make it so.