The United States has significantly curtailed its joint military exercises with South Korea, a move that has unsettled the longstanding alliance and reignited debate in Seoul about strategic self-reliance — including, for some, the once-taboo question of nuclear weapons.

President Donald Trump directed the Pentagon to "substantially" scale back the combined drills, leading to the flagship annual Ulchi Freedom Shield exercise being shortened from 11 days to five, with other field training events reduced or cancelled outright. The South Korean marine corps also confirmed that separate joint drills originally scheduled for September were cancelled, with Washington citing competing demands related to its ongoing war in Iran. Trump framed the exercises as costly and provocative, describing them as sending "a totally inappropriate and hostile" signal to North Korea — a country he said has been "unthreatening and respectful" during his presidency. He also openly linked the decision to Seoul's refusal to support the US military campaign in the Middle East, underlining what critics see as an increasingly transactional approach to treaty alliances.

Security analysts have responded sharply. Bruce Klingner, a senior fellow at the Maureen and Mike Mansfield Foundation, called the exercise cuts a "trifecta of failure," arguing they degrade allied deterrence, penalise a dependable partner and reward Pyongyang without extracting any concessions. He warned that North Korea — currently buoyed by an estimated $14–20 billion in food, fuel and military technology from Russia, as well as resumed trade with China and around a billion dollars annually from cryptocurrency theft — has little incentive to engage diplomatically with Washington. Klingner assessed the probability of a Trump-Kim summit, which some observers expect Trump may pursue at the Asia-Pacific Economic Cooperation forum in Shenzhen in November, as "slim to none."

In South Korea, the cumulative effect of the cuts has deepened anxieties about whether American security guarantees remain unconditional. A recent survey found roughly 80% of South Koreans support the country developing its own nuclear arsenal, up from 64% in 2013. President Lee Jae-myung has stopped short of endorsing nuclear weapons but has pushed for Seoul to reclaim wartime operational control — currently held by the US — and oversaw a defence budget increase of more than 7% this year. South Korea is also pursuing nuclear-powered attack submarines using low-enriched uranium, a technology held by only six other countries.

Experts caution that the path to greater autonomy carries its own risks. Going nuclear would expose South Korea to retaliatory sanctions under the Nuclear Non-Proliferation Treaty, which it ratified in 1975, and could erode the considerable international goodwill Seoul has built through decades of commitment to multilateral norms. Others warn that becoming more militarily indispensable could paradoxically draw South Korea deeper into regional conflicts it has so far managed to avoid. The debate, once marginal, now sits at the centre of South Korean strategic thinking — a direct consequence, analysts say, of Washington's shifting posture toward its oldest alliances.