US President Donald Trump has scaled back major joint military exercises with South Korea, just days after his administration publicly hailed the alliance as entering a "historic new era". The pullback reportedly followed Seoul's refusal to support American operations against Iran, marking an abrupt shift in tone towards a key Asian ally and raising questions about the durability of US security commitments in the region.

The reversal came only three days after Secretary of State Marco Rubio praised South Korea as an "indispensable partner", building on goodwill from Trump's state visit to Seoul the previous autumn. According to Victor Cha, Korea Chair at the Center for Strategic and International Studies, several factors drove Trump's decision: frustration over delays to trade and investment agreements, a wish to revive engagement with North Korean leader Kim Jong Un, and a belief that wealthy South Korea should bear more of the cost of its own defence.