US, South Korea and Japan prepare nuclear and missile drills amid new uncertainty in Asia

The United States, South Korea and Japan will hold joint military exercises in September focused on the threat posed by North Korea’s nuclear and missile programmes. The Freedom Edge exercise is scheduled for September 9–11 in international waters south and east of Jeju Island. According to South Korea’s Joint Chiefs of Staff, the drills will be defensive in nature and are intended to test the three countries’ readiness to respond to a potential crisis.

The exercise will include air and missile defence, anti-submarine warfare and cyber defence. It therefore goes beyond a demonstration of military presence, instead deepening the operational interoperability of the three countries’ forces as they increasingly coordinate their deterrence systems around North Korea’s nuclear and missile programmes.

Washington is simultaneously scaling back exercises with Seoul

The announcement of new trilateral drills is particularly significant against the backdrop of Donald Trump’s decision to reduce the scale of some US-South Korean military exercises.

In August, the US president ordered the Pentagon to significantly reduce the scale of joint military exercises with Seoul, arguing that such activities could be perceived by North Korea as hostile. Washington also cancelled planned US-South Korean Marine Corps exercises scheduled for next month.

The decision formed part of a broader effort by Trump to create conditions for renewed direct dialogue with Kim Jong Un. The US president has already signalled his willingness to return to the diplomatic format used during his first term, when he met the North Korean leader twice.

Yet scaling back some exercises does not amount to abandoning military deterrence. Freedom Edge demonstrates that the US, South Korea and Japan continue to build a joint system for responding to North Korean missile launches and a potential nuclear crisis.

North Korea is not reducing military pressure

Pyongyang has already demonstrated in August that US signals about a possible return to dialogue have not prompted it to halt its missile activity.

On August 20, North Korea launched around 10 ballistic missiles towards the sea as US and South Korean exercises were nearing their conclusion.

North Korean authorities have also repeatedly condemned military cooperation between the US, South Korea and Japan, arguing that it is effectively developing into a new form of nuclear alliance. Pyongyang traditionally portrays such exercises as preparations for a potential military operation against North Korea.

This creates a fundamental dilemma for Washington’s diplomatic strategy. The US is trying to keep the door open to negotiations with Kim while simultaneously reassuring its allies that American security guarantees remain intact.

For Tokyo and Seoul, the issue goes beyond North Korea

Trilateral military coordination is becoming increasingly important for Japan and South Korea not only because of the number of missile launches carried out by Pyongyang. Both countries are closely watching changes in US strategy across the Indo-Pacific.

Trump’s decision to scale back some joint exercises has already raised questions about the reliability of American security guarantees. The moves have fuelled concerns among key US allies in Asia about the long-term American military presence in the region and Washington’s willingness to fulfil its commitments.

For South Korea, the issue is particularly sensitive. Seoul supports Trump’s efforts to revive dialogue with North Korea while seeking to prevent any weakening of its own deterrence system. It is effectively trying to combine diplomatic engagement with Washington with the need to maintain maximum readiness for a potential military crisis.

Asia’s security architecture is becoming less predictable

Freedom Edge highlights an important shift in East Asia’s security architecture. Even as Washington seeks to reduce military tensions surrounding North Korea, its allies continue to deepen practical military coordination.

This could become one of the most significant long-term consequences of the current US policy. If allies begin to question the stability of American security guarantees, they have a stronger incentive to develop their own military capabilities and coordinate more closely with one another.

The debate in South Korea over whether the country should strengthen its own nuclear capabilities is particularly significant. Against the backdrop of reduced US exercises and the continued expansion of North Korea’s nuclear arsenal, questions over how far Seoul should rely on the American nuclear umbrella are once again moving higher up the political agenda.

Trump’s diplomatic manoeuvring around Kim Jong Un could therefore produce a paradoxical effect. Washington is seeking to reduce tensions in order to bring North Korea back to the negotiating table, but uncertainty surrounding US military commitments is simultaneously encouraging South Korea and Japan to strengthen their own deterrence capabilities.