U.S. Secretary of State Antony Blinken and Defense Secretary Lloyd Austin left East Asia on Thursday, having reassured allies, reasserted American diplomacy and outlined foreign policy priorities on the first Cabinet-level overseas trip of the Biden administration.

But the trip also showed divergent interests and policy approaches among the allies to the two issues that loomed large over the visit: North Korea's growing nuclear arsenal and China's growing assertiveness.

"We welcome the return of America, the return of diplomacy and return of alliances that started with the inauguration of the Biden administration," South Korean President Moon Jae-in told Blinken and Austin on Thursday at the Blue House, Seoul's equivalent of the White House.

Moon added that he would work closely with the United States for the denuclearization of the Korean Peninsula.

But both countries' officials used conflicting language about denuclearization, making it unclear whether North Korea is obliged to denuclearize unilaterally, or if the United States is expected to reciprocate by removing its "nuclear umbrella," defending South Korea, as Pyongyang demands.

Just ahead of Blinken's remarks, North Korean First Vice Foreign Minister Choe Son Hui confirmed in a statement that the North Korean government had intentionally ignored U.S. efforts to contact it and would continue to do so until Washington dropped its "hostile policy."

She singled out the Americans' "groundless rhetoric about 'complete denuclearization,' " adding "we will keep tabs on all the ill deeds the new regime in the U.S. is engrossed in."

While the U.S. and South Korea share democratic values, their policies are not completely aligned, said Kim Hyun-wook of the Korea National Diplomatic Academy in Seoul.

China is another example of this divergence. Blinken and Austin repeatedly asserted that China threatens regional stability and security, but the South Korean hosts did not repeat the idea in their remarks, or a joint statement.

"The Biden government wants South Korea to partner with the United States in deterring China," Kim said, but "South Korea wants the Biden government to be more oriented towards dialogue with North Korea, rather than sanctioning and pressuring" Pyongyang. The two sides can better align their priorities through compromise, he added.

On this issue, Blinken and Austin had somewhat better luck in Tokyo, where Japan joined the United States in criticizing China in a joint statement.

Given the shift of public opinion against China in Japan, "the Japanese reluctance regarding naming names, with respect to China, is already a sort of outdated thing," said Yoshihide Soeya, a professor emeritus at Keio University in Tokyo.

One of the key goals of the Blinken-Austin trip, Soeya said, was "to keep Japan on the side of the U.S ... and I think they have succeeded in doing this."

But longer term, Japan and other midsize powers in the region are hedging their bets by strengthening ties among themselves, Soeya said, in case China one day displaces the U.S. as the dominant power in Asia, and Tokyo can no longer count on Washington.

"We have to learn how to live under the shadow of China," Soeya said. "Building networks of cooperation among regional countries – this is the ultimate China strategy, on our part."

Another key mission of the Blinken-Austin trip, Soeya noted, was to heal the serious rift between Japan and South Korea — which are the two main U.S. allies – and the region's most advanced economies and democracies.

Historical feuds over World War II-era history and Japan's 1910-1945 colonization of Korea have thrown relations between the two neighbors into a tailspin, undermining economic and security cooperation.

Moon has recently extended olive branches to Tokyo, indicating he's willing to cooperate, but there was no public statement of a consensus on this issue between Blinken and his Japanese hosts.

Blinken will meet with Chinese counterparts in Alaska on Thursday and Friday.

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Tags: U.S.  South Korea  North Korea