South Korea negotiated tariff protection for its chipmakers, and Washington is pressing for American factories anyway. Semiconductor investment is now part of the broader talks between the two governments, a presidential official in Seoul has confirmed.

The confirmation was reported by Reuters, and it follows Washington signalling plans for targeted tariffs on semiconductor imports.

Howard Lutnick has put the American position in a single sentence. “If you don’t build here, expect to pay to enter the greatest market in the world,” the commerce secretary said.

Seoul thought it had already settled this. Under the agreement struck between the two presidents, South Korea committed $350bn towards US manufacturing investment in return for tariff terms “no less favourable” than those given to competitors with comparable chip trade volumes.

That clause is the crux of the disagreement. It promises parity rather than exemption, which means Korean chipmakers are protected against being singled out but not against a tariff that lands on everyone.