Biden Shifts Focus Back to U.S. Alliances in Japan, South Korea

But on Wednesday, as the two officials arrived in Seoul, the pins were gone, a recognition that the matter carries less weight in a South Korea that currently gives priority to engagement with the

Kim Jong Un

regime.

After four years of relative U.S. inattention to its allies, President Biden has pledged to rebuild ties with foreign friends, choosing two partners central to Washington’s challenges with a rising China and an increasingly nuclear North Korea.

“It’s no accident we chose [South Korea] for the first cabinet-level overseas travel of the Biden-Harris administration, along with Japan,” said Mr. Blinken on Wednesday in Seoul.

Japan and South Korea, both of which rely heavily on the U.S. military for their defense, place an unusually high emphasis on receiving American diplomatic affection—and notice if either side ever receives more of it. For decades, Tokyo and Seoul have been angling to become Washington’s favorite ally in the region.

This has meant fretting over every word uttered by U.S. officials, over which Asian ally is first awarded a presidential phone chat and over which side earns the backing of the U.S. in disputes that have ranged from history to national security.

When the U.S. last week invited Japanese Prime Minister

Yoshihide Suga

to the White House, becoming the first world leader to be asked to Washington by the Biden administration, South Korean media seethed and urged President

Moon Jae-in

to push for a trip of his own.

“President Moon, too, must visit the U.S. on a not-too-distant date,” read an editorial in the Seoul Shinmun, a partially government-owned daily newspaper more than a century old.

Getting two very different, though interlocked, countries to get along is an important task for the U.S. Both Japan and South Korea host tens of thousands of American troops. The two U.S. allies play central roles in some of Washington’s most vexing foreign-policy challenges, including China, North Korea and Russia.

“We are working to strengthen America’s relationships with our allies as well as the relationships among them,” Sung Kim, acting U.S. assistant secretary of state for East Asia, said last week. “And none are more important than Japan and the Republic of Korea.”

Mr. Biden, while a presidential candidate last year, wrote an editorial for South Korea’s semiofficial news agency praising the two countries’ alliance. After taking office in January, Mr. Biden’s administration arranged a three-way meeting with Seoul and Tokyo to discuss North Korea. In recent weeks, the U.S. agreed to military cost-sharing deals with both South Korea and Japan—moves that had been difficult under former President

Donald Trump,

who often attacked the two allies for not paying enough.

This week, both Tokyo and Seoul have avoided publicly airing their disputes with each other. One Seoul government adviser said South Korea wasn’t offended by the U.S.’s choice of Japan as the trip’s first stop.

“We accept that Japan is a stronger country than us,” the adviser said. “That’s international order, and that’s just the truth.”

But ties between Tokyo and Seoul remain rancorous. The two are fighting a trade dispute that is under review by the World Trade Organization. Tensions erupted after a string of South Korean court decisions pulled World War II-era forced-labor issues into the present day.

The Japanese have been refusing to even talk with South Korea, say officials and advisers from both countries. Mr. Suga declined to meet with the outgoing South Korean ambassador in Tokyo earlier this year and has yet to meet the new ambassador.

On March 1, Mr. Moon repeated a proposal to Japan, offering to revive talks to sort out their disagreements. The gesture has gone unanswered in Japan so far.

The two countries’ acrimony has created security issues. In 2019, Japan’s unexpected trade sanctions prompted South Korea to threaten withdrawal from an intelligence-sharing pact that had been backed by the Obama administration and could help coordinate a response during a military crisis.

Over the decades, the U.S. has often found itself in the middle, or the cause of, disputes between Japan and South Korea.

When then-President

Barack Obama

met with South Korea’s leader during his first term, the two leaders described their alliance as the “linchpin” of Northeast Asia. The U.S. had described its alliance with Japan as the region’s “cornerstone.”

Afterward, a former U.S. official began receiving multiple phone calls from Japanese officials asking if “linchpin” was more important than “cornerstone,” said Brad Glosserman, a senior adviser to the Hawaii-based think tank Pacific Forum, who had talked with the former official.

“That’s proof of how silly that rivalry can be,” Mr. Glosserman said. The U.S. hasn’t since changed the way it refers to each ally.

Last year, when Mr. Trump extended a guest invitation to South Korea for the Group of Seven nations meeting, Japanese officials pushed back. Mr. Suga, at the time Tokyo’s top government spokesman, stressed the importance of keeping the current G7’s framework. An official at South Korea’s presidential office accused Japan of shamelessness.

The one-upmanship even included the sequencing of Mr. Biden’s phone calls to world leaders after his January inauguration. Keeping with tradition for U.S. leaders, Mr. Suga connected first, while Mr. Moon got a call a week later.

But South Korean officials spun this to a positive: They have privately noted that Mr. Moon’s exchange lasted two minutes longer than Mr. Suga’s.

— Alastair Gale contributed to this article.

Write to Andrew Jeong at andrew.jeong@wsj.com