Regarding the Philippines’ South China Sea policy towards China, analysts generally agree on the following two points: First, during the Presidential campaign, Ferdinand Marcos Jr. initially attempted to resolve the South China Sea issue through traditional diplomatic means,[1] but after he became President, he decided to strengthen military deterrence in alliance with the United States.[2] Secondly, the Philippines originally agreed to China’s joint-development agreement, using a bilateral approach to deal with the South China Sea disputes. However, Marcos Jr. later shifted to multilateral cooperation with various countries to defend the Philippines’ sovereignty in the region.[3] In other words, the administration of President Marcos Jr. appears to be recalibrating its approach to the South China Sea by seeking greater international involvement, particularly from countries like the United States, Japan, Australia, and India. This policy shift signals a move toward multilateral engagement to bolster the Philippines' sovereignty claims and strengthen its position in dealing with China. A key aspect of this realignment is the decision to align more closely with the United States, reviving and deepening security ties. What remains unclear, however, is why this pivot occurred: What factors prompted Marcos Jr. to revise the Philippines’ South China Sea policy? Why is the Philippines choosing to align more closely with the United States? And what are the implications of this shift for regional security and diplomacy?

During Marcos Jr.’s presidential campaign, he was the most China-friendly of the 10 candidates. In January 2022, Marcos Jr. was interviewed by foreign media; he stated that if elected, he would continue to put aside the 2016 South China Sea arbitral ruling because he believed that it would be the “only practical option” to reach a bilateral agreement with Beijing to deal with the evolving conflict situation.[4]

In addition, Marcos Jr. allied with his predecessor’s daughter, the vice- presidential candidate Sarah Duterte, speaking highly of President Duterte’s China policy. Another reason that people believed that Marcos Jr. was pro-China was because his father, the former president of the Philippines, established diplomatic relations with China in 1975.

In Marcos Jr.’s first year in office that he adopted a similar approach to Duterte’s China policy. At that time, Marcos Jr. attempted to shelve the South China Sea dispute in exchange for economic and trade benefits from China. In the first stage, Marcos Jr.’s China policy and handling of the South China Sea dispute were initially seen as a continuation of his predecessor Rodrigo Duterte’s diplomatic strategy of being “pro-China” and “anti-American”.

However, starting in 2023, less than a year after taking office, Marcos Jr. showed a completely different attitude towards the South China Sea issue than when he ran for president. First, in February 2023, the Philippines and the United States reached the Enhanced Defense Cooperation Agreement (EDCA), under which the Marcos Jr. administration allowed U.S. troops to rotate in the Philippines and build facilities at Philippine bases.[5] In addition to the original five bases, Marcos Jr. announced in April 2023 that he had approved the establishment of four more US military bases in the region.

The move was a response to China's growing expansion in the South China Sea. As President of the Philippines, Marcos Jr. decided to restore the US- Philippines military partnership because he believed that the United States would be its ally as well as an external power that could help the Philippines compete with China.

At the end of 2023, on December 19, in response to the South China Sea issue, Marcos Jr. began to publicly admit that it was useless to use “traditional diplomatic means” to deal with China's aggressive behavior in the South China Sea. Therefore, he announced a shift towards adopting alternative approaches to address the South China Sea issue. Subsequently, during his visit to Japan and attendance at the “ASEAN-Japan Commemorative Summit on the 50th Anniversary of Relations,” Marcos Jr. publicly stated that, guided by the standard principles outlined in the United Nations Charter and the Treaty of Amity and Cooperation in Southeast Asia, the Philippines would establish a “free, open, and rules-based Indo-Pacific region” with friendly nations.[6] The US and Japan-led Indo-Pacific strategic framework has become one of his response strategies to address the South China Sea issue.

A week later, during a joint air and sea patrol exercise involving the Philippines, the US, and Australia, a spokesperson for the Philippine Armed Forces reiterated Marcos Jr.’s statements, indicating that the Philippines would showcase its modernized military capabilities in the future and engage in bilateral and multilateral joint patrols with allied countries in the South China Sea. This shift highlights that Marcos Jr. is transitioning the focus from diplomatic means to military responses in addressing the South China Sea issue. In addition to reinforcing the Philippines' stance in defending its territorial sovereignty, strategically proposing to “strengthen our alliances with foreign countries, so that our voice will be stronger, we can also enhance legal processes to promote our interests, and promote regional peace and stability.”

The ongoing dispute between China and the Philippines in the South China Sea serves as a foundation for reinvigorating the military alliance between the United States and the Philippines and restoring partner relationships. As a result, the United States has actively enhanced military cooperation with the Philippines, and the latter has begun to strengthen military alliance relationships with allies such as Japan, South Korea, and Taiwan. James R. Holmes, a professor of maritime strategy at the U.S. Naval War College, believes that the Philippines' return to the U.S. alliance allows the U.S. military to move closer to the “gray zone” of the South China Sea conflict zone. It also enhances the U.S. military’s presence which can support Manila and other potential military partners in the region. Moreover, at the northern end of the first island chain, the U.S. military has been collaborating more closely with Japan. The Japanese Self-Defense Forces has also strengthened defense efforts in the Okinawa Islands.

In early 2023, Marcos Jr. shifted towards a clear military approach to counter China's gray zone tactics.[7] Firstly, there has been a continuous strengthening of military countermeasures in the Philippines, with a determination to incorporate more military deployments to defend territorial waters. This was evident in April 2024 when President Marcos Jr. signed Executive Order No. 57, establishing the National Maritime Commission (NMC), expanding military forces, taking a firmer sovereignty stance, and attempting to counter the “illegal, coercive, provocative, and dangerous attacks” of the Chinese Coast Guard. Secondly, there has been a strengthening of relations with the United States and other Indo-Pacific partners, with the Marcos Jr. government expanding U.S. military presence in the Philippines beyond base establishment and conducting a series of joint patrols and military exercises to highlight the strength and deterrence of the U.S.-Philippines military alliance. Additionally, the Marcos Jr. government has established a series of new security partnerships, including elevating Australia to a strategic partnership in September 2023 and initiating security cooperation with the Vietnamese Coast Guard in January 2024.

In April 2024, in response to the South China Sea issue, the U.S.-Philippines- Japan held a trilateral summit in Washington, confirming multi-level cooperation among the three countries, including military assistance to the Philippines, joint maritime and aerial patrols, and regular joint military exercises to counter China's strategies in the gray areas of the South China Sea and create a deterrent effect.[8] Experts believe that a multilateral cooperation framework is crucial for the Philippines to maintain sovereignty in the South China Sea. This kind of multilateral cooperation expands the issue of the South China Sea from the perspective of protecting Philippine sovereignty to maintaining international freedom of navigation in the region. This is the new response model that the Marcos Jr. government has established in response to the South China Sea issue, involving militarization and internationalization as countermeasures.

Marcos Jr.’s predecessor, Duterte, also shifted his policy towards China. When he became president, he faced China's gray-zone strategies in the South China Sea. He chose a softer approach for economic reasons. In November 2017, he met Chinese President Xi Jinping in Vietnam. He announced a new chapter in relations with China. However, after 2021, Duterte later changed his approach, and began to assert sovereignty. For example, on March 7, 2021, when over 200 Chinese fishing vessels anchored at Whitsun Reef in the South China Sea, Philippines' Defense Secretary Lorenzana publicly accused China of taking “provocative actions that militarize the area.” The Philippines subsequently deployed its navy and coast guard to conduct patrols in the area and also sent a fighter jet for aerial surveillance. The reason he did that was he was unhappy that China did not fulfill certain promises.

After June 3, 2022, the Marcos Jr. administration came into power. Marcos Jr. continues to manage this complex relationship in a similar way. Regarding the South China Sea issue, before taking office, Marcos Jr. publicly stated that “he would engage in dialogue with China with a ‘firm voice' and would not allow Philippine rights to be ‘trampled upon,’ but he also referred to Beijing as the country’s ‘most powerful partner’ in the recovery from the pandemic.”

It is evident that in the early stages of his administration, Marcos Jr. still leaned towards employing a stalling approach, primarily using diplomatic means to address the issue. According to a special report by Philippine media outlet Rappler on August 23, 2023, Chinese Coast Guard vessels targeted Philippine coast guard ships with military-grade lasers, once again escalating the attack posture against Philippine supply ships. In response to this, Marcos Jr. continued to refer to and position this area of the sea as a gray-zone in interviews. In September 2023, Marcos Jr. instructed the National Task Force for the West Philippine Sea to adopt a “civilianized approach” in addressing the issue of the Second Thomas Shoal.

However, on October 22, 2023, a Chinese Coast Guard vessel obstructed a Philippine resupply mission to Second Thomas Shoal and fired water cannons at the resupply ship.[9] This incident was regarded as one of the most serious diplomatic conflicts between the two nations in recent years. At the time, Filipino Foreign Secretary Teodoro Locsin conveyed “anger, condemnation, and protest” to China's Ambassador to the Philippines, Huang Xilian, and the Chinese Ministry of Foreign Affairs in the strongest terms, reminding China that its vessels were protected under the US-Philippines Mutual Defense Treaty. On November 22 2023, the "30th Anniversary Commemorative Summit of China-ASEAN Dialogue Relations" was held, with Xi Jinping in attendance. Duterte, in his remarks, directly called on China to respect the United Nations Convention on the Law of the Sea of 1982 and the 2016 Hague arbitral ruling.

In 2025, there are increasingly tense maritime confrontations between China and the Philippines. On March 5 2025, a China Coast Guard vessel blocked a Philippine resupply mission at Second Thomas Shoal, making the Philippine government take a hard stance against China to protect sovereignty and national interest. Therefore, it is not surprising that Marcos Jr.’s policy shifted toward China because of the escalating tensions between the Philippines and China since 2021 in the South China Sea.

In conclusion, there are three main reasons President Marcos Jr. changed his China policy in the South China Sea:

First, the support of the U.S. and Japan played a significant role in making Marcos Jr. adopt a new China Policy. U.S. Defense Secretary Lloyd Austin’s visit to Manila in January 2023 facilitated even deeper US-Philippines security cooperation. Since U.S. President Biden had demonstrated his commitment to defend the Philippines if China took aggressive actions toward the Philippines in South China Sea disputed waters, especially the second Thomas Shoal, this influenced Manila to have strong determination to defend itself and have confidence that is beneficial for the Philippines to align closely with the U.S. under the Indo-Pacific strategy.

Secondly, Marcos Jr. relies more on the Philippine Armed Forces, which is another reason why he takes an anti-China stance. Traditionally, the Philippine Armed Forces supports a pro-America stance, and also favor a tougher approach to China. Therefore, it made Marcos Jr. contrast with his predecessor Duterte’s pro-China policy.

Third, anti-China sentiment is growing in the Philippines, with more and more people supporting the United States over China. Domestic sentiment is very important, and public opinion is likely to prompt Marcos Jr. to take a tougher stance against China, because he has to adopt a policy that is in line with the preferences of the majority of people, and protect the national interests of the Philippines.

These factors combined to push Marcos Jr.’s China policy away from engagement and towards a more confrontational approach to China, but aligned with the United States and Japan and guided by domestic preferences.

In April 2025, General Romeo Browner publicly stated that if China invaded Taiwan, the Philippines would “inevitably” be involved.[10] What are the implications for Taiwan? As the Philippines’ stance indicates a shift toward a more proactive regional security posture, we can also see that during the Marcos administration, the Philippines emphasizes collective defense and its alliance with the United States when facing China’s aggressive behavior in the South China Sea. This signal shows that Taiwan can seek to establish a closer security partnership with the two countries in the Indo-Pacific region. Additionally, it may encourage the establishment of diplomatic relations and personnel exchanges between Taiwan and the Philippines, especially after the Philippine government eases restrictions on official exchanges with Taiwan on April 22, 2025.