On July 23, South Korean fighter jets fired more than 300 warning shots at a Russian military aircraft that violated airspace claimed by Seoul as it was conducting a joint air patrol with China.
Around the same time, Japan scrambled combat aircraft to warn off the Russian and Chinese planes flying near islands claimed by both Japan and South Korea in the Sea of Japan. Moscow vehemently disputed Seoul's version of events but Tokyo subsequently confirmed that the South Korean version was accurate.
Unilateral military incursions into disputed areas in Northeast Asia have become more common, but Russian planes have never violated South Korean airspace in this manner. Moreover, an incident involving China and Russia on one side and Japan and South Korea on the other is unprecedented.
The latest incident should not be dismissed as an isolated event. It is further confirmation that a military quasi-alliance between China and Russia is emerging where both countries assist each other in undermining the U.S. and its allies despite the absence of formal commitments to defend each other against attack.
The important lesson is that Tokyo and Seoul should be drawing closer together in response to the emerging military cooperation between Beijing and Moscow.
China and Russia are authoritarian countries that oppose the U.S. championing democratic principles. Russia seethes about the breakup of the Soviet Union and the subsequent loss of Moscow's global influence, while China believes it should be the dominant power in Asia.
Both countries view the U.S. as the main culprit in precipitating the collapse of the Soviet Union and preventing the rise of China. Their solution is to undermine the U.S. alliances with Japan and South Korea and divide the allies so that it becomes far more difficult for Washington to maintain its forward presence around the world.
Asia is particularly vulnerable because the region lacks a collective security agreement such as the North Atlantic Treaty Organization. The troubled history between Japan and South Korea continues to create tensions between these two U.S. allies.
Nonetheless, Japan is looking outward and playing a strategic game. Under Prime Minister Shinzo Abe, the country has transformed itself into the most powerful and important U.S. ally in the region. Its air force and navy remain a match for China's People's Liberation Army in Northeast Asia, while Japan is developing its own quasi-military alliance with Australia.
Under the banner of making a "proactive contribution to peace," Japan is joining Australia and the U.S. in defending what they call a "Free and Open Indo-Pacific" against the expansionist ambitions of China and Russia.
Missing in action is South Korea. It is a formidable Asian military and economic power. But President Moon Jae-in remains committed to the "Three No's" he promised China in return for Beijing ending an informal trade boycott against South Korea that it imposed after Seoul deployed an antimissile system in 2016 to defend itself against a potential North Korean missile attack.
The "Three No's" included no further U.S. anti-ballistic missile systems, no South Korean integration into a regional U.S. missile defense system and no trilateral military alliance with the U.S. and Japan.
These concessions amount to a strategic reward to China after it caused an estimated $10 billion economic loss for South Korea when the former administration of President Park Geun-hye tried to protect its citizens.
At the same time, distracted by a rerun of historical grievances against Japan, South Korea's current policy willfully ignores the reality that the existential military threat to Seoul comes from Pyongyang. The latter is ruled by a regime that survives only due to Chinese and Russian succor and protection.
Japan must accept some responsibility and has a role to play in making an alliance with South Korea easier to achieve. Recently, Tokyo took the step of turning a diplomatic dispute into an economic one, with its tightening export controls of key materials to South Korea's chipmaking industry. That tightening could be reversed in return for Seoul being more willing to move on from regularly reigniting historical grievances.
In any event, Seoul's argument that United Nations Security Council sanctions ought to be relaxed against North Korea does not make sense as it will only increase the capacity of Pyongyang to further perfect its illegal nuclear weapons.
Softer gestures will not increase the security for South Koreans or those living in Japan. Remember that if North Korean leader Kim Jong Un unleashes his nuclear arsenal, Japan and South Korea are the primary targets.
Beyond the Korean Peninsula, the fact that Chinese aircraft joined the Russian sortie is early but credible evidence that a Beijing-Moscow quasi-military alliance will only increase their resolve to intimidate and divide U.S. allies.
The better move would be to persuade Beijing and Moscow that joint mischief-making against U.S. allies is counterproductive to Chinese and Russian interests and not worth the effort. The best way to achieve that is for Moon to walk back the "Three No's," which would give South Korea a powerful card that it could play to its enduring advantage.
China is fearful that the integration of an enhanced U.S.-led anti-ballistic missile defense system with Japan and South Korea will severely compromise its own land-based missile offensive capabilities even if the system is ostensibly to protect its allies against North Korea.
A genuine trilateral military alliance among the U.S., Japan and South Korea would profoundly spoil Chinese and Russian plans to divide and weaken U.S. allies. For the sake of the health of the U.S.-led alliance system and its own national interests, South Korea needs to obtain more leverage against China and Russia.
Beginning the discussion to change the "No's" into "Maybe's" or even abandon them will give much leverage to Seoul. It will also help South Korea to lend its considerable weight to the "Free and Open Indo-Pacific" strategy of the U.S., Japan, Australia and India and counter the authoritarian challenge of China and Russia.
John Lee, a former senior national security adviser to the Australian foreign minister, is a senior fellow at the Hudson Institute and the United States Studies Centre at the University of Sydney where he is an adjunct professor.