In a significant shift in defence strategy, the Pentagon has outlined plans to reduce its role in deterring North Korea, with South Korea set to take on primary responsibility for the task. This move, outlined in a recently released Pentagon policy document, is likely to raise concerns in Seoul as it grapples with the evolving security landscape on the Korean Peninsula.
The National Defence Strategy, which guides the Pentagon’s policies, stated that “South Korea is capable of taking primary responsibility for deterring North Korea with critical but more limited US support.” This shift in the balance of responsibility is described as “consistent with America’s interest in updating US force posture on the Korean Peninsula.”
The document suggests that in recent years, some US officials have signalled a desire to make US forces in South Korea more flexible, allowing them to operate outside the Korean Peninsula in response to a broader range of threats, such as defending Taiwan and countering China’s growing military reach.
South Korea, which hosts around 28,500 US troops as part of the combined defence against North Korea’s military threat, has resisted the idea of shifting the role of US troops. However, the country has worked to grow its defence capabilities over the past 20 years, with a view to taking on wartime command of the combined US-South Korean forces. South Korea currently has a military of 450,000 personnel.
The shift in responsibility is part of what Washington has called “alliance modernisation” under the Trump administration. South Korean President Lee Jae Myung has himself pushed for greater defence autonomy, criticising in September what he called “the submissive mindset that self-reliant defence is impossible without foreign troops.”
In a statement on Saturday, South Korea’s defence ministry said US Forces in Korea remained central to the alliance and would continue to deter North Korean aggression. However, the Pentagon document makes no mention of denuclearising the Korean Peninsula, a goal that was explicitly stated by the Biden administration in 2022, suggesting a potential shift in Washington’s approach towards managing North Korea’s nuclear arsenal rather than seeking its elimination.
The wide-ranging Pentagon document, which is published by each new administration, states that the priority is defending the US homeland. In the Indo-Pacific region, the document says the Pentagon is focused on ensuring China cannot dominate the US or its allies, without specifically mentioning Taiwan.
This latest development in the US-South Korea defence relationship reflects the evolving strategic priorities of both countries as they navigate the complex security challenges in the region. As South Korea takes on a greater role in deterring North Korea, the alliance will continue to be a critical component of the broader geopolitical landscape in East Asia.
