Why South Korea must brace for ‘worst-case scenario’ as Trump reduces military drills

Lee’s statement comes at a time when South Korea and the US began their annual Ulchi Freedom Shield exercises, which were originally scheduled to run for 10 days. The drills are designed to test the allies’ ability to respond to a potential conflict with North Korea.

Trump, however, directed Defense Secretary Pete Hegseth to “substantially reduce” the exercises, saying that continuing them at their planned scale could send an inappropriate and hostile signal to Pyongyang.

The decision has raised questions about the future of the US-South Korea military alliance and whether Washington’s approach toward North Korea is once again shifting towards diplomacy.

Why Lee is talking about the ‘worst case scenario’

Lee said maintaining peace was “most important” for South Korea, but added that the country must also be prepared for the possibility that efforts to maintain stability could fail.

The South Korean president has long supported strengthening the country’s own defence capabilities while maintaining its alliance with the US. Following Trump’s decision to reduce the exercises, Lee renewed his call for Seoul to regain independent wartime control of its military.

“A strong alliance makes the foundation of security stronger, and strengthening our own capabilities increases our value and necessity as an ally,” Lee said in a cabinet meeting.

The issue is particularly significant because South Korea does not currently have full wartime operational control, or Opcon, over its forces.

South Korea regained peacetime control of its military from the US in 1994. However, wartime operational control remains with the allies’ Combined Forces Command, which is headed by a US four-star general.

Lee wants the planned transfer of wartime control to South Korea to continue during his term. The annual exercises were partly intended to help assess and certify Seoul’s ability to assume that responsibility.

What are the Ulchi Freedom Shield exercises?

Ulchi Freedom Shield is one of the main annual military exercises conducted by South Korea and the US.

The drills began on Monday and were expected to involve about 18,000 South Korean troops, along with US forces and personnel from 11 of the 18 member states of the United Nations Command.

The exercises are officially defensive. Seoul says they are intended to improve military readiness and prepare for different scenarios rather than practise an attack on North Korea.

On Tuesday, Lee’s presidential office said the drills did not show “any intention to attack North Korea or escalate tensions on the Korean peninsula”.

Lee’s office said their fundamental purpose was “not to treat a specific entity as an adversary, but to safeguard the safe and peaceful daily lives of the people”.

North Korea, however, has consistently rejected that explanation. Pyongyang has described the exercises as a rehearsal for an invasion.

North Korea’s foreign affairs ministry said last week that “By doing so, [the U.S.] did not conceal its aim to complete preparations for the substantial military confrontation” with North Korea.

“This is tantamount to an admission that the exercises, which the U.S. and the ROK describe as ‘annual’ and ‘defensive’ ones, are a rehearsal for an aggressive war,” it added.

Why did Trump order the drills to be reduced?

Trump’s decision appears to be closely linked to his renewed efforts to engage North Korean leader Kim Jong Un.

In a Truth Social post on Sunday, Trump described his relationship with Kim as “very good” and said North Korea had been “unthreatening and respectful”. He has previously taken a similar approach to US-South Korean military exercises.

After his first summit with Kim in 2018, Trump suspended the Ulchi Freedom Guardian exercise. Other large-scale exercises were also suspended or reduced as Washington and Pyongyang pursued negotiations.

The drills were later redesigned and resumed in modified forms under different names.

Victor Cha, Korea chair at the Center for Strategic and International Studies, said Trump could once again be using military exercises as a diplomatic tool to send a message to Kim.

Speaking on a CSIS podcast, Cha said “this is not something that is unusual. We have seen the president use military exercises as a tool in the past.”

Cha also suggested that the timing could serve another purpose for Trump, as the US president faces continuing attention over the conflict with Iran.

“Trump’s tired of Iran … so he’s shifting to something else.”

Why the decision is important for South Korea

The US has maintained a military presence in South Korea since the Korean war. About 28,500 US personnel are stationed there through US Forces Korea.

The two countries remain closely linked militarily because the Korean war ended in 1953 with an armistice rather than a formal peace treaty. Technically, the two Koreas remain at war.

The alliance has therefore been central to South Korea’s security for decades. However Trump’s decision to reduce the exercises has also shown Seoul’s long-running effort to strengthen its independent military capabilities.

Lee has called for faster progress on the transfer of wartime operational control. He has also urged the government to speed up South Korea’s nuclear-powered submarine programme and develop officers capable of handling integrated military operations in future conflicts.

The idea is not necessarily to reduce dependence on the US. Instead, Lee argues that a stronger South Korean military can make the alliance more effective.

Why North Korea remains a concern

Trump has described North Korea as relatively unthreatening, South Korean and US military officials continue to regard Pyongyang as a serious security threat.

North Korea has also strengthened its military relationship with Russia since signing a comprehensive strategic partnership pact with Moscow in June 2024.

Pyongyang has provided troops, artillery ammunition and ballistic missiles to support Russia’s war against Ukraine. US and South Korean officials say North Korean forces have gained battlefield experience from the conflict, including experience involving drones.

Those developments have been incorporated into this year’s exercises. Col Ryan Donald, the public affairs director for the US-led commands in South Korea, told CNBC that North Korea’s battlefield experience had changed the threat environment.

“They’ve taken those lessons they learned there and brought them back to North Korea, that changes the DPRK capability,” he told CNBC. “Our training accounts for that threat, that is why the exercise looks different [from previous exercises], and over the last five years it’s continually evolved.”

What happens next?

Trump’s decision puts Seoul in a difficult position. South Korea wants to maintain peace and avoid unnecessary escalation with North Korea, but it also needs to ensure that its forces remain prepared for a sudden deterioration in security.

The issue has become even more complicated because Trump has also criticised Seoul over its response to the US conflict with Iran.

On Monday, Trump said, “We have 39,000 soldiers over there guarding you from Kim Jong Un, your next door neighbor, and you’re not going to help us on a very easy military operation in Iran.”

South Korean officials have said they are discussing possible military and practical contributions with Washington while taking into account the security situation on the Korean peninsula and South Korea’s domestic legal procedures.