South Korean activists hold a rally in front of the Japanese Embassy in Seoul on July 11, denouncing Japan's tightened controls on exports of high-tech materials to South Korea. (Yonhap/EPA-EFE/Shutterstock)

Evan S. Medeiros is a professor in Asian Studies at Georgetown University and previously served on the National Security Council staff during the Obama administration.

There is a crisis unfolding in Asia, and few are paying attention. Not least the U.S. government, which is probably the only actor that can fix it.

Two of the United States’ core allies — Japan and South Korea — have become deeply estranged. Earlier this month, the bickering broke out into a nasty trade war. The conflict threatens not only the U.S. alliance network but also regional prosperity and global supply chains. On Wednesday, South Korean President Moon Jae-in called relations with Japan an “unprecedented emergency.”

Despite Asia’s phenomenal economic, social and technological progress, history looms over the region like a dark shadow. Unresolved grievances related to invasion, occupation and colonization continue to influence perceptions and behavior across the region.

Specifically, South Koreans harbor deep resentment about Japan’s colonization of the country from 1910 to 1945 and feel they have not been adequately compensated. Japan harbors deep frustration about its multiple and substantial efforts — dating back to the normalization of diplomatic relations in 1965 — to amend for its past crimes.

The latest drama unfolded because South Korea’s Supreme Court last year ordered Japanese companies to pay compensation for forced labor during colonization. Tokyo’s position is that the 1965 normalization agreement waived reparations. South Korea’s position, based on the court decision, is that the agreement does not apply to individuals.

Recently, a South Korean court ordered the seizure and distribution of a Japanese company’s assets, which crossed Tokyo’s red line. Japan retaliated by imposing tight restrictions on critical exports to South Korean semiconductor companies that build components for chips that go into smartphones, tablets and a host of industrial electronics. According to Bloomberg, Japan’s action mainly affects Samsung Electronics and SK Hynix, which account for a combined 60 percent of global memory-chip-making capacity.

The geopolitical and economic costs of this conflict are substantial and rising. Both sides may have technical merits to their arguments, but they are myopically damaging their larger diplomatic and economic interests, as well as those of the United States.

First, alliance cohesion is critical to U.S. strategy in northeast Asia. Regional security challenges posed by North Korea and China require that Washington and its allies maintain unity. Due to the latest tensions, trilateral defense cooperation needed to prepare for North Korean aggression has basically stalled.

North Korea and China know this. Both have — separately and in parallel — tried to put further distance between South Korea, Japan and the United States during periods of tension among the allies.

Second, China under Xi Jinping has assumed a more active and aggressive posture throughout Asia, especially on maritime territorial issues. Xi would probably do more if not constrained by U.S. alliances. China would love for U.S. forces to leave the Korean Peninsula, to have a freer hand to coerce Taiwan and to establish effective control over waters in the East China Sea and South China Sea.

The current Japan-South Korea conflict does China’s work for it. It provides a permissive environment to pull South Korea away from both the United States and Japan. It creates more space for Beijing and Tokyo to flirt with each other, dangerously validating the Chinese belief that Japan’s reliance on China is growing and that these alliances are ultimately malleable.

Third, Japan’s actions legitimize a dangerous practice: implementing unilateral sanctions of questionable legal basis against specific industries in the service of diplomatic retaliation.

China did this against Japan in 2010 when it banned exports to the island nation of rare earth elements. And in 2016 and 2017, China took more far-reaching actions against several South Korean companies after Seoul agreed to deploy a U.S. missile defense system.

If U.S. allies now get into the game of blatant economic coercion, these actions risk triggering a cycle of retaliation that would destabilize regional trade and global supply chains — for a continent that accounts for nearly two-thirds of global economic growth.

The United States can and should act, but with discretion. Washington is the only actor both sides will listen to. President Trump should call both leaders today and encourage them to stop the trade actions and begin talking. He should direct Secretary of State Mike Pompeo to travel to both Tokyo and Seoul as soon as possible. If needed, the president should meet with Japanese Prime Minster Shinzo Abe and South Korea’s Moon at the next available opportunity.

There is precedent for this. In 2014, during a low point between Seoul and Tokyo, President Barack Obama quietly held a meeting with both countries’ leaders during an international summit. The situation was so bad at the time that Abe had not yet met his South Korean counterpart, President Park Geun-hye, about a year into her term.

This private discussion stopped the freefall, put a floor under relations and created a framework to rebuild ties. Importantly, the leaders agreed that disputes over history should not undermine security cooperation. They decided to resume, and augment, defense cooperation on the North Korean nuclear threat.

Now would be a good time for the current administration to show leadership by impressing upon our allies the damage being done and the larger strategic interests at stake.