The United States and South Korea are marking their seventy-year alliance with a state visit amid tighter defense collaboration. But the alliance “forged in blood” should now evolve to be powered by chips, batteries, and clean technology.

Presidents Biden and Yoon pledged to deepen and broaden the scope of the U.S.-South Korea alliance, but their success could depend on how China, Japan, and North Korea respond.

The United States and South Korea should pursue an expanded nuclear agreement that supports the production of civilian nuclear power and enhances extended deterrence against the North Korean threat. …

President-Elect Yoon Suk-yeol has pledged to strengthen ties with the United States and take a more hard-line approach toward China and North Korea than his predecessor.

The vote for South Korea’s next president is taking place in a fractious political environment and is likely to bring a foreign policy neophyte to power.

North Korea seeks to exploit major-power rivalries and weaken U.S.-South Korea ties with its ramped-up missile testing. Already, it has ratcheted up nuclear tensions on the Korean Peninsula to their …