- US allies Japan and South Korea are increasingly at odds, and on Thursday, the latter decided to cancel an agreement to share intelligence with Japan.
- Experts say the damage to the alliance works in China's favor. "It weakens the United States' toolkit for fighting back against China's illiberal aims and ambitions," Kristine Lee, an Asia-Pacific security expert, told Insider.
- The latest developments come as the new secretary of defense, Mark Esper, is focusing intently on China. He recently said that China is the Pentagon's "number one priority."
- Visit Insider's homepage for more stories.
Two US allies in East Asia are at odds, delivering a serious blow to US security interests while potentially handing a big win to China.
South Korea said Thursday that it plans to end an intelligence-sharing agreement with Japan, arguing that the pact is not in its "national interests." The decision marks the latest move in an escalating rift between the two nations.
The General Security of Military Information Agreement (GSO MIA) was an important step forward for two countries that have long struggled to work together and that share a troubled history. The strategic bilateral agreement helped align the two nations defensively against regional threats.
The possible collapse of the agreement amid an intensifying trade dispute between South Korea and Japan has significant implications for the US alliances, especially as the US confronts China's rising regional power, and experts are worried.
'It weakens the United States' toolkit for fighting back against China's aims and ambitions'
"There are significant repercussions to the disintegration of GSOMIA," Kristine Lee, a research associate for the Asia-Pacific Security Program at the Center for a New American Security, explained to Insider Friday, adding that this development to the advantage of countries like North Korea and China.
"When Japan and South Korea, two of the region's most vibrant democracies, are sparring, China is looking at all of this with bemusement."
"They are able to exploit rifts between the United States' greatest alliances in the region and use it to their advantage," Lee said. It weakens the United States' toolkit for fighting back against China's illiberal aims and ambitions."
"China is the biggest winner here," Rob Spalding, a former senior member of President Trump's National Security Council, explained to Defense One, arguing that this development hands China "a potent weapon to chip away" at the alliance structure.
These two countries are essential to basing US power in the region. The US has 23,000 troops stationed in South Korea including tanks, artillery and F-16 fighters, and has stationed two Terminal High Altitude Area Defense systems there. And Japan hosts 50,000 US troops and is a base for about 20 US warships, including the US's only forward-deployed aircraft carrier.
Airman 1st Class Matthew Seefeldt/US Air Force
'Strong concern and disappointment'
The Department of Defense expressed "strong concern and disappointment" with South Korea's decision.
"We strongly believe that the integrity of our mutual defense and security ties must persist despite frictions in other areas of the [Republic of Korea]-Japan relationship. We'll continue to pursue bilateral and trilateral defense and security cooperation where possible with Japan and the ROK," the Pentagon said in a statement Thursday.
Lee told Insider that the status or health of the East Asian alliance tends to go through cyclical periods of tension, optimistically explaining that "we always tend to come back from them."
The Trump administration, which has been critical of both South Korea and Japan, has been less supportive of traditional alliances.
Commenting on the rising tensions between South Korea and Japan, President Trump said in July, "How many things do I have to get involved in? It's like a full-time job getting involved between Japan and South Korea."
The damage to the alliance comes at a time when the Department of Defense is focusing intently on China. In his first television interview since he became the new secretary of defense, Mark Esper, told Fox News that China is the Pentagon's "number one priority."
"Looking across the Asia-Pacific region, all of the regional democracies, with South Korea and Japan at the forefront, they all view China as a significant, long-term threat to their security in the 21st century," Lee told Insider. "That should be a unifying factor. If the United States is able to leverage that common view of long-term perceptions, it will be able to rebuild the alliance structure."
"Alliances," Lee said, "are the United States' greatest force multiplier, so if it is able to harness that and ease over tensions with Japan and South Korea, it could position itself for long-term enduring strength in the region." This begins with assurances and increased support for trilateral engagements, but that will require this administration and future administrations invest appropriately in that future.