[Choi Junyoung's World+] US, Japan, and Philippines Trilateral Summit and South Korea's Dilemma

First Trilateral Summit at the White House
Joint Response to Philippine Maritime Incursions
Encircling China Through Small-Scale Security Cooperation
Expanding the Role of Japan Self-Defense Forces and US Forces in Japan
Japan’s Role Grows with AUKUS Membership
South Korea Must Broaden Its Diplomatic and Security Perspective

Legal Specialist at Yulchon LLC (Global Law & Policy)

On April 11, the leaders of the United States, Japan, and the Philippines held a joint summit at the White House. Following the US-Japan summit on April 10, a US-Philippines summit was held, followed by the trilateral summit. The main reason for the trilateral summit was to demonstrate the support of the US and Japan for the Philippines amid the clashes between the Philippines and China in the waters called the West Philippine Sea by the Philippines and the South China Sea by China.

China claims most of the South China Sea as its territorial waters regardless of international maritime law. This claim dates back to the era of Chiang Kai-shek’s Kuomintang government, but due to a long-standing naval disadvantage, China had not taken concrete actions. However, in the 1990s, when the US Navy stationed in Subic Bay, Philippines, withdrew at the request of the Philippine government, China began to assert its power. The Chinese military occupied the Mischief Reef, which the Philippines considered its territory. Naturally, the Philippine government strongly protested, but China began constructing structures on the reef from 1994 to turn it into its territory, and from 2014, it intensified land reclamation work, completing the militarization of the base by deploying a 2,650-meter-long runway, radar, and missiles. To counter China’s occupation, the Philippine government grounded a ship on the Second Thomas Shoal near Mischief Reef in 1999, turning it into a maritime base where the Philippine Marines could stay.

U.S. President Joe Biden (center) speaks ahead of the trilateral summit with Japanese Prime Minister Fumio Kishida (right) and Philippine President Ferdinand Marcos Jr. at the East Room of the White House in Washington, D.C., on the 11th (local time). Photo by AP and Yonhap News Agency

Although both sides claimed sovereignty, the area remained relatively calm until 2014, after which it became a site of intense clashes. The Chinese Coast Guard and maritime militia have been blocking the Philippine military’s supply routes to the Second Thomas Shoal. China isolates Philippine Coast Guard vessels and blocks them, attacking the following supply ships with water cannons to prevent resupply. During these water cannon attacks, Philippine supply ships have been damaged and personnel injured. For the Philippines to maintain the base, regular resupply is necessary, and although missiles have not appeared, both sides engage in fierce clashes resembling warfare each time. Given China’s overwhelming power, the Philippines faces significant difficulties. In 2016, the International Arbitration Tribunal ruled that China’s so-called nine-dash line in the South China Sea has no legal basis and that China is illegally occupying the Philippines’ exclusive economic zone (EEZ), but China has ignored this ruling and continues provocations.

Facing this crisis, the Philippines has recently been actively restoring relations with the US to counter China. The US and the Philippines signed a Mutual Defense Treaty in 1951, but military cooperation weakened after the rise of Philippine nationalism in the 1990s. The inauguration of President Rodrigo Duterte, who openly pursued a pro-China policy, was decisive. Duterte advocated economic and military separation from the US, announced joint resource exploration with China in the South China Sea, and participation in the Belt and Road Initiative, openly showing pro-China moves. However, as public resentment grew due to China’s repeated incursions into Philippine waters, Duterte belatedly sought to improve relations with the US. His successor, President Bongbong Marcos, has further strengthened cooperation with the US.

In 2023, the US and the Philippines conducted large-scale military exercises involving 17,000 personnel, and the Philippines authorized the US military to use four of its military bases. In August 2023, the US Secretary of Defense confirmed that the US-Philippines Mutual Defense Treaty applies to Philippine ships and aircraft throughout the Pacific region, including the South China Sea, showcasing US support for the Philippines. Against this backdrop, the trilateral summit of the US, Japan, and the Philippines clearly signaled a three-nation alliance to check China in the South China Sea.

The Biden administration is actively leveraging allies alongside direct confrontation to block China’s maritime expansion. Recognizing that forming a large-scale security community like Europe is unrealistic, the US is sequentially establishing multiple small-scale security cooperation frameworks involving two to three countries centered on the US. Starting with AUKUS in 2021, which includes the UK and Australia, the Quad comprising Australia, Japan, and India was formed, and in 2023, the Camp David summit formalized enhanced military cooperation among South Korea, the US, and Japan. Recently, a small-scale security cooperation framework involving Japan and the Philippines in the South China Sea was reestablished, strengthening the maritime encirclement of China. The US-Japan summit announced enhanced interoperability between the Japan Self-Defense Forces and US forces stationed in Japan, with the South China Sea likely becoming a primary theater of operations.

Since World War II, the US Navy has dominated the world’s seas, but it has recently shown signs of strain in competition with China. China’s industrial production, owning half of the world’s shipbuilding capacity, is outpacing the US. To overcome this disadvantage, the US is strengthening cooperation with allies, expanding Japan’s role in the process. The US has allowed its warships to be maintained and repaired at Japanese shipyards, and at the recent summit, announced the initiation of procedures to admit Japan as a Pillar 2 member of AUKUS.

For South Korea, responding to this situation requires expanding our security and diplomatic perspective beyond the Korean Peninsula to at least the Indo-Pacific region and engaging in more proactive military cooperation and activities. It is necessary to take the lead in appropriately intervening in regional issues, showing a willingness to handle and assist with tasks that the US alone cannot manage. Additionally, vague rejection and hostility toward Japan must be overcome, and discussions on mutual role-sharing as a full-fledged alliance should be pursued.

Choi Jun-young, Legal Expert at Yulchon LLC (Global Law & Policy)