US Naval Power Gap, Reaching Out to South Korea

The U.S. Center for Strategic and International Studies (CSIS) mentioned South Korea's Dosan Ahn Chang-ho-class submarines as an allied force to be deployed in the path of Chinese aircraft carriers. While Japan's Aegis destroyers are primarily defensive, the Dosan Ahn Chang-ho-class is equipped with offensive hunter-killer capabilities, making it highly strategically valuable. This suggests that the South Korean naval force can play an important role in the international strategic environment.

Despite military cooperation with North Korea, Russia tends not to completely sever economic ties with South Korea. This is because it considers long-term economic cooperation with South Korea and opportunities to participate in post-war reconstruction projects. Even if Russia urgently needs immediate support during the war, it judges that South Korea could be a more important partner than North Korea in the future.

The U.S. Chief of Naval Operations visited South Korea and emphasized the need for South Korea's key assets to counter Chinese and Russian nuclear submarines. This reflects U.S. concerns about the increasing naval power of China and Russia in the Western Pacific, particularly their nuclear submarine forces. The U.S. Navy has shown its willingness to respond to these security threats through cooperation with its ally, South Korea.

The United States operates 11 supercarriers of 100,000 tons, but the typical operational period for one carrier is a maximum of six months. However, major carriers such as the USS Ford and USS Lincoln are currently conducting long-term operations exceeding 300 days. These prolonged operations lead to crew fatigue and family issues, negatively impacting operational efficiency and troop morale.

U.S. Navy ships typically operate in a cycle where one-third are in repair, one-third are in training and rest, and only one-third are deployed for operations. As a result, only four to five carriers can actually be operated simultaneously. With the U.S. responsible for global operations, this limited operational rate raises concerns about a power vacuum in critical regions like the Western Pacific.

As of the end of 2024, the number of major vessels in the Chinese Navy has surpassed that of the U.S. Navy, with 370 ships compared to 297. This shows that the Chinese Navy quantitatively outnumbers the U.S. The U.S. has seen its ability to build new ships significantly weakened due to the collapse of its domestic shipbuilding industry and is also experiencing problems with aging vessels and a lack of repair capabilities.

While the U.S. Navy must operate globally, the Chinese Navy primarily operates in its own coastal waters. This global mission burden and prolonged operational periods exacerbate the fatigue of U.S. Navy crew members. There are even instances of sailors attempting suicide due to operational stress, indicating a severe manpower shortage in addition to the aging U.S. Navy fleet.

Compared to conventional submarines, nuclear submarines have overwhelming speed and operational range, making it virtually impossible for conventional submarines to pursue them. Nuclear submarines can operate at high speeds for extended periods without refueling, which is a critical factor in countering the nuclear submarine forces of China or Russia. If South Korea were to possess nuclear submarines, it could significantly reduce the operational burden on the U.S. Navy.

South Korea's Dosan Ahn Chang-ho-class submarine is an excellent platform with outstanding hunter-killer capabilities, but it has the limitations of a conventional propulsion system. In particular, unlike nuclear submarines, its high-speed maneuvering time is limited by battery issues, posing restrictions in combat. Therefore, its ability to track and counter Russian and Chinese nuclear submarines is clearly limited, and arguments are being made that South Korea's possession of nuclear submarines is essential for this purpose.

The U.S. Navy is currently facing challenges with an aging fleet and manpower shortages, and thus desperately needs South Korea's help. Establishing a cooperation system between the U.S. and South Korean navies in both ship maintenance and new ship construction is seen as an essential task, not an option. A similar context can be found in the past when former President Trump requested war assistance from South Korea.

China and Japan have long been at odds over hegemony in Northeast Asia, a conflict intertwined with Sinocentrism and Japan's pride in its modernization. The sovereignty dispute over the Senkaku Islands (Diaoyu Islands in Chinese) is a major factor escalating tensions between the two sides. The Senkaku Islands, fifty times the size of Dokdo but without resident troops, are a strategically important area, and the conflict surrounding them significantly impacts Northeast Asian security.

One of the main reasons for the worsening relations between China and Japan is the ongoing Senkaku Islands dispute. Japanese Prime Minister Takaichi's remarks regarding Japan's potential intervention in a Taiwan contingency sparked controversy over China's territorial sovereignty. Such statements further escalate tensions between the two countries.

Japan's Self-Defense Forces have participated in the Balikatan (shoulder-to-shoulder) exercise in the Philippines for over a decade. In a recent exercise, they dispatched virtually their largest combat contingent and conducted a ground-to-ship missile launch drill for the first time post-war. This is interpreted as Japan's willingness to actively intervene in Southeast Asian regional security.

Japan has long maintained the principle of exclusive defense (military force solely for defense). However, it reached a turning point in 2015 when the Abe government introduced a new concept of 'enemy base attack capability.' Based on this concept, Japan decided to introduce Tomahawk missiles and is shifting its policy from defense-oriented to offensive force enhancement.

Japan plans to deploy ground-to-ship missiles on Yonaguni, its westernmost island, about 180 km from Taiwan. This region is a strategic choke point between China and Taiwan, and the missile deployment aims to counter China's military movements. This move by Japan could further escalate military tensions in the East China Sea.

Japan has recently established an Amphibious Rapid Deployment Brigade, equivalent to a marine corps, to acquire amphibious operation capabilities. The amphibious training of the brigade is interpreted as being in preparation for recapturing island territories such as the Senkaku Islands. This shows that Japan is strengthening its territorial claims in disputed areas and preparing for military responses if necessary.

The territorial dispute between Russia and Japan over the Kuril Islands (including Iturup and Kunashir) continues. In the past, President Putin offered to return some of the Northern Territories (Shikotan and Habomai) to Japan, but Japan refused. Subsequently, President Putin escalated military pressure by conducting nuclear missile launch drills in the region. These actions by Putin raise the possibility of military ties with China.

Recently, joint military exercises by China and Russia have become frequent in the East Sea. This suggests that China is constantly looking for opportunities to expand into the East Sea. Strategies linking with North Korea, such as Wang Huning's visit to Wonsan, show China's intention to extend its influence into the Pacific through the East Sea, posing a new threat to Northeast Asian security.