The U.S. nuclear-powered submarine Columbia arrives in Busan. Yonhap News. 

 China is expected to take countermeasures against South Korea's pursuit of nuclear-powered submarine (NPS) development, an expert on South Korea-U.S. relations and Korean Chair at the Center for Strategic and International Studies (CSIS) Victor Cha observed on the 6th (local time).

Speaking on the CSIS podcast that day, Cha stated that President Lee Jae-myung has recently shown a much stronger strategic tilt towards the U.S. in summit talks with the U.S. and China, adding, "I would not be surprised if China later takes action in response to the nuclear submarines."

Cha noted that the U.S. approval of South Korea's NPS development was "quite unexpected," saying, "I don't think Xi Jinping (Chinese President) would have expected it at all."

He added, "So, while Xi Jinping couldn't react at all (during the summit), he has already responded to the South Korea-U.S. shipbuilding cooperation by sanctioning South Korean companies (Hanwha Ocean) against U.S. companies. So I wouldn't be surprised if China does anything in the future to economically coerce South Korea."

The observation suggests that China, having previously sanctioned a U.S. subsidiary of Hanwha Ocean, which plays a key role in South Korea-U.S. shipbuilding cooperation, will also seek to check South Korea-U.S. NPS cooperation.

Cha also commented that South Korea and Japan have accommodated President Donald Trump's demands in trade and security to maintain their alliances with the U.S., asking, "I wonder how long they will do that. At some point, will they finally say, 'We're going to go with Plan B'?"

In response to this question, Georgetown University Professor Evan Medeiros, who was in charge of China at the White House National Security Council (NSC) during the Obama administration, diagnosed that for the U.S.'s core Asian allies, namely Japan, South Korea, and Australia, there is "virtually no Plan B" to replace the U.S.

He argued that all three countries rely on their bilateral alliances with the U.S. for security, and since there is no multilateral alliance like NATO in Europe in Asia, they have no choice but to maintain their alliances with the U.S. to counter threats from China and others.

Medeiros stated that South Korea and Japan have no choice but to maintain their relationship with the U.S. not only for access to the U.S. market but also for access to U.S. technology and capital in areas like artificial intelligence (AI) and semiconductors.

However, he pointed out that the absence of a Plan B applies only to South Korea, Japan, and Australia, adding, "If you assume that this structure also applies to other Asian allies like the Philippines and Thailand, that would be a misjudgment."

Yonhap News