Background
When you think of important bodies of water, the Pacific ocean or the Red Sea may come to mind. However, a small sea west of the Pacific is often overlooked. It may serve as the staging ground for a major conflict, one that could inevitably result in a war between two major superpowers. Serving as one of the most important bodies of water in the world, the South China Sea provides essential resources for the Philippines, Brunei, Malaysia, Indonesia, Vietnam, and of course, China. Many people rely on the South China Sea as a source of income, a way to put food on the table, and a route of transportation. So, what has caused tensions in The South China sea? And how close are we to war?
The nine dash line and Chinese aggression towards the Philippines
In December of 1947, China published a map of the South China Sea, with dashes claiming 90% of the sea’s’ many islands. However, China has firmly reiterated many times that their assertion is a historical one, not a territorial one.
In an article in the June 2013 issue of China National Geography, Shan Zhiqiang, the executive chief editor of the magazine, wrote the following statement: “Some people claim that the ‘Nine-dash Line’ is the line of island ownership, which is a big mistake.” … “The ‘Nine-dash Line’ is certainly not a national boundary line. National boundaries do not allow foreigners to pass freely, which is obviously not feasible in the South China Sea. The Nine-dash Line is the ‘historic waters’ line. In addition to other permitted rights such as allowing foreign ships to pass freely in the waters it encloses, all other rights belong to China.”
Under the direction of the United Nations, any country has exclusive rights to explore, exploit, and manage marine resources in the waters 200 nautical miles off of their coastline. On July 12th, 2016, the tribunal concluded that China had not exercised exclusive control over the waters within the nine-dash line historically and has “no legal basis” to claim “historic rights” to the resources there. China’s policies would have no lawful effect beyond what it is entitled to under the UNCLOS.
Despite officially stating that they would allow other countries to pass through the area enclosed by the Nine Dash Line, China has put up a firm effort to keep one country out: the Philippines.
China regularly sends military patrol ships to Philippine waters, a display of unwarranted force to ward off others. On February 6th, 2022, the Chinese Coast Guard blocked Filipino resupply ships from resupplying Second Thomas Shoal, a hotly contested area home to a grounded Filipino ship. Both countries claim the shoal, and with about a dozen Filipino Marines, it is vital to make their presence known. Chinese sailors used a military grade laser to blind Filipino sailors, marking it as one of the first incidents that have physically harmed Filipino personnel. In the end, food and supplies were unable to reach the marines on the grounded ship.
Another notable incident occurred in 2024, where Philippine vessels were attacked by the CCG (Chinese Coast Guard) again while attempting to resupply its sailors on Second Thomas Shoal. The CCG blasted ships and sailors with water cannons and boarded them, brandished axes and knives, slashed inflatable rafts, attempted to tow boats away, and constantly rammed them, unfortunately costing a Filipino sailor his thumb.
In an interview in 2024, Harrison Pretat, Deputy Director and Fellow, Asia Maritime Transparency Initiative, CSIS, explained, “If that was his arm, instead, maybe he bleeds out and dies, and then you have a U.S. treaty ally who’s just had a soldier die in a conflict with China in the South China Sea.”
This escalation is incredibly important–there is now an opening for the Philippines to activate their Mutual Defense Treaty with the U.S., where America is obligated to help defend the Philippines, its oldest treaty ally in Asia, if Filipino forces come under an armed attack. This is not the first time Filipino sailors have been injured as a result of Chinese attacks. For example, in March of 2024, three sailors were critically injured by a water cannon. It’s a clear sign that China is willing to fight back harder as attacks like these are becoming more common.
Philippines pushback
What has the Philippines done to resolve the situation, as China has been constantly expanding and showing presence in the region? Over the years, former presidents have taken varied approaches, with Benigno Aquino III pushing back hard against any advances into Philippine territory. In 2015, he took China to international court over the highly contested Scarborough Shoal, winning a majority of their proceedings in 2016. Aquinio publicly criticized China’s actions and improved ties with the U.S.
Despite the tense relationship, the next president, Rodrigo Duturte, took a lighter stance and focused on strengthening ties with China, while retaining their strong U.S. partnership. Meeting with president Xi Jingping multiple times, he downplayed the 2016 win and allowed China to build and maintain military bases on many islands in the South China Sea. Al Jazeera reports that Duterte has been reluctant to confront China over the issue as he tries to foster a closer friendship with the economic giant.
Current president Bongbong Marcos has made his stance clear: the Philippines will not relinquish any territory and will push back against Chinese aggression. Since taking office in 2022, Marcos has filed multiple diplomatic protests to challenge the advancements. He has strengthened Filipino ties with the U.S. and neighboring countries, presenting a unified front to deter the Chinese. Under the Enhanced Defense Cooperation Agreement (EDCA), Marcos has approved the expansion of U.S. access to Philippine military bases, enhancing joint training and rapid deployment for the allies in case of an emergency.
Additionally, President Marcos stated in a speech after a conflict between the Chinese and Philippine coast guard on February 6th, 2023, “This country will not lose one inch of its territory. We will continue to uphold our territorial integrity and sovereignty in accordance with our constitution and with international law. We will work with our neighbors to secure the safety and security of our people.”
In addition, the Philippines has signed a defense agreement with New Zealand, Japan, Australia, and have engaged in discussions with France to bolster their defense. In collaboration with the US and Japan, the Philippines has conducted joint naval exercises in contested areas of the South China Sea, demonstrating a unified front against coercive actions.
The chance of U.S. involvement
Currently, the Philippines does not have the ability to fend off the largest navy in the world on their own. Neither does Vietnam, Brunei, or Malaysia. Most countries, especially Brunei, rely on Chinese exports to maintain their economy, while Taiwan is reluctant to increase tensions with China. Other surrounding countries desire to avoid war at all costs. However, the Philippines has a significant backer–the United States. Since the end of U.S. colonial rule in the Philippines in 1946, the U.S. has been a key ally, with President Truman pledging unwavering support should the Philippines need it. The Philippines has also been extraordinarily important to U.S. influence in the region. Not only is its geographical position perfect to conduct trade, the U.S. is able to station naval forces close to allies like Thailand and Taiwan, and deter possible threats like China and North Korea.
The U.S. has made it incredibly clear that this partnership is rock solid and will endure into the future. In a joint press conference on July 31th, 2024, Former Secretary of State Antony J. Blinken explicitly stated, “we stand by our ironclad defense commitment to the Philippines.” Trump’s administration seems to continue to hold their partnership strong. Current United States Secretary of Defense Pete Hegseth reiterated the U.S.’s support, affirming in a joint media session on March 28th, 2025 that “our partnership not only continues today, but we are doubling down on that partnership, and our ironclad alliance has never been stronger.”
The future
Going forward, neither side looks willing to back down. The American/Philippine partnership will continue with the Trump Administration. With the closening ties between the Philippines and its neighbors, Chinese deterrence has become a major sticking point to President Trump’s Indo-Pacific strategy. Exercise Balikatan, meaning shoulder to shoulder in Tagalog, began on April 21st, 2025. This year marks the 40th iteration of one of the largest bilateral military exercises between the U.S. and Pacific allies, enhancing military interoperability and readiness in case of any emergency.
As tensions continue to grow, there is no question that China will respond physically. They have already made statements condemning the actions of the U.S. and its Pacific partners. Tian Junli, spokesperson for China’s Southern Theater Command, explained the Philippines’ actions were “an attempt to endorse its ‘illegal claims’ in the South China Sea and “undermine China’s maritime rights and interests.”
Despite the reluctance to begin a war, U.S. friendly countries like Japan and Australia have been strengthening their military might. The increasing effort from both sides seem to demonstrate both countries bracing for war. Is the world really ready for an all out conflict between two major superpowers?
“This country will not lose one inch of its territory. We will continue to uphold our territorial integrity and sovereignty in accordance with our constitution and with international law. We will work with our neighbors to secure the safety and security of our people” said Philippine President Marcos in a speech on February 6th, 2023.