By Liu Jiwen

Recently, the US and the ROK have shown different positions on some military cooperation issues, reflecting the cognitive disparities between the two sides in their judgment of regional security situations and ways of alliance and cooperation, further indicating that the US-ROK alliance is facing new challenges.

Lack of synchronization in the joint exercise

The US and the ROK planned to hold a joint military exercise codenamed Freedom Shield from March 9to 19. However, the release of exercise-related plans pre-scheduled on February 25 was delayed because the two sides failed to reach an agreement on the scale of the exercise.

The ROK preferred a moderate reduction of the exercise scale, especially a significant shrinkage of field maneuver training, to mitigate the tense regional military situation.

Nevertheless, the US insisted on keeping the established intensity of the exercise and had implemented the deployment of the participating troops and equipment according to the initial plan. In its view, the large-scale joint exercise is an important platform to examine the combat readiness and demonstrate their deterrence. Any unprepared adjustments in the scale will possibly lead to pressure on logistics and coordination, thus degrading the effectiveness of the alliance's deterrence.

As a matter of fact, there have long been indications of a rift in the relationship between the two countries. At the beginning of 2026, the ROK declined the proposal by the US concerning a trilateral joint air exercise by the US, the ROK, and Japan, citing the proximity of the proposed exercise to the ROK's Seollal (Korean Lunar New Year) and Japan's so-called "Takeshima Day". It further suggested that the exercise be changed to only involve the ROK and the US.

However, the US rejected the suggestion and carried out a bilateral joint maritime exercise with Japan in mid-to-late February. It has been interpreted by foreign media as a response by the US to the ROK, indicating that the US doesn't mind any negative effects on US-ROK relations.

Deepening rift caused by misalignment in strategic demands

The rift in the US-ROK alliance stems from their misalignment in strategic demands. For the US side, due to the priority given to great power competition and maintaining its military superiority, it requires the ROK's military operations to be in line with the strategic direction of the US. The US implements its own will on the joint exercise tempo, force deployment, and other specific issues, putting aside the geopolitical and security pressures the ROK faces.

By contrast, the ROK hopes to retain strategic resilience in the alliance framework. While it needs to rely on the security assurance provided by the US, the ROK is unwilling to get overly involved in the great power competition dominated by the US. It is more inclined to focus US-ROK military cooperation on the security affairs of the Korean Peninsula. The ROK is afraid that excessive military operations will potentially intensify regional tensions and thereby jeopardize its own development interests.

The differences between the US and the ROK on issues such as military exercise plans, sharing of defense spending and regional security policies may persist in the coming period. It's hard for the two sides to return to synchronization. The possible US continuation of blindness to the ROK's geopolitical security concerns and unilateral actions on key issues will further erode the foundation of mutual trust within the alliance.