By: Adinda Khaerani Epstein, Adjunct Fellow

Brief Historical Background

Southeast Asia is known as a region prone to territorial disputes, which present a serious challenge to regional stability. The experience of colonial rule was one of the contributing factors due to arbitrary demarcation. One security challenge of note in the region derived from complex territorial disputes centers around the South China Sea (SCS).

The body of water is one of the largest semi enclosed seas in the world with an area of 648,000 square nautical miles and encompasses vital routes linking the Pacific and Indian Oceans with $5.35 trillion worth of trade passing its waters annually, almost one-third of all global maritime trade. Equally contributing to the significance of the SCS is what lies underneath: oil, gas and potential hydrocarbon reserves.

The SCS is highly contentious with China and four other Association of the Southeast Asian Nations (ASEAN) member states — Brunei, Malaysia, the Philippines and Vietnam — involved in disputes featuring the Spratly and Paracel Island chains being contested. Although most of the disputes involve China, Vietnam and the Philippines, recent tensions primarily have been between Beijing and Manila.

From eleven to nine – dash line

China claims almost the entirety of the SCS, popularly visualized as the “nine-dash line”. It was first shown on a Republic of China-issued map in 1947 with an 11-dash line and later the Chinese Communist Party adopted the map in 1949 with two dashes removed to give the Gulf of Tonkin to Communist North Vietnam.

In 2009, China reinforced the map’s international status by submitting a diplomatic note to the UN Commission on the Limits of the Continental Shelf with the attachment of a nine-dash line map, the day after Malaysia and Vietnam submitted their joint submission, and claimed that Beijing has indisputable sovereignty over the islands in the SCS.

However, it hasn’t been clear what the nine-dash line signifies. Does China claim the bits of reef and land inside the line or does China claims all surrounding waters?

Geopolitical complexity in the disputed waters has become more apparent due to the intensified great power rivalry between China and the United States. The issue was brought up for the first time in 2010 at the multilateral platform that is internationally recognized as one of the world’s strongest forums when it comes to the SCS, the ASEAN Regional Forum (ARF). Vietnam brought up the issue at that time to then-U.S. Secretary of State Hillary Clinton. She expressed that Washington has national interest in open access to Asia’s maritime commons, freedom of navigation, as well as respect for international law in the SCS, despite maintaining neutrality in the disputes. The attempt from Vietnam to internationalize the issue to get a solution was understandable, given the power asymmetry between China and other disputants. On the other hand, Beijing has always been clear about its preference in solving the disputes with direct bilateral negotiations and perceived the role of the U.S. in the disputes as an interference; this sentiment remains to this day.

Serious clashes from 1974 involving China, Vietnam and the Philippines

However, it is important to note that even before the statement from China that indicated the involvement from the U.S. will only make the matters worse, disputes have already involved serious clashes.

The deadliest of these incidents was the Sino–South Vietnam battle of the Paracel Islands in 1974 and Johnson South Reef skirmish in 1988. The Paracels, composed of 130 small coral islands and reefs, are presently claimed by Vietnam, Taiwan and China, but have been under the latter’s control when it forcibly ejected South Vietnamese troops from the chain, in the process killing 74 Vietnamese service members. The latter clash, located in the southwestern Spratly Islands, saw Chinese forces drive off the Vietnamese military presence and resulted in the deaths of 64 Vietnamese sailors and marines.

A significant incident without fatalities occurred in early 2012, when China and the Philippines were involved in a standoff at Scarborough Shoal located in the northern Spratlys. Both countries claim the shoal as a part of their national territory and accused each other of intruding on the other. Two years later, tensions rose over China’s placement of a giant state-owned oil rig inside Vietnam’s Exclusive Economic Zone (EEZ). This incident marked the first time that Beijing had sent one of its oil rigs into another state’s EEZ without prior permission. The clash featured the ramming of boats between the two and an explosion of large anti-China protests inside Vietnam.

Looking at the dynamic of the tensions, especially over the past decade, the disputants appear under no illusion that such incidents won’t be repeated in the future. As a result, closer defence cooperation between Vietnam and especially the Philippines with Washington has increased.

Tension between China and the U.S., however, was accentuated during the pandemic. The Trump administration insisted that China needed to be held accountable for the spread of the Covid–19 virus. While other governments were distracted with the outbreak throughout 2020, Beijing managed to build up activities in the disputed islands by establishing administrative districts on the Spratly and Paracel islands.

In the same year, the U.S. had toughened the stance by officially rejecting specific claims made by China in the disputed waters for the first time. The Biden administration adopted a similarly strong position. During her 2022 visit to Jakarta for the ASEAN summit, Vice President Harris stated that America was in the region to stay, giving reassurance to allies that Washington had their backs. One may argue whether Washington’s strategy has been effective in deterring Beijing’s increasingly aggressive moves, but the gradual change of tone was clear. The U.S. also has a major role in the region by conducting Freedom of Navigation operations and sent military aircraft and warships into the South China Sea.

In July 2023, Vietnam, in a display highlighting just how important it considers territorial integrity matters, preemptively banned the Hollywood movie Barbie over a scene featuring the disputed nine–dash line on a cartoon map. A recent Center for Strategic and International Studies report showed that Hanoi has accelerated its land reclamation and dredging activities some seven-fold over the past three years. However, the ramping up to approximately 2,360 acres pales in contrast to China’s activities, which measure some 4,650 acres since 2013.

A month later, prior to the ASEAN Summit, China’s Ministry of Natural Resources unveiled its “standard map” with a tenth dash added to the east, which includes eastern part of Taiwan. Vietnam, Taiwan, Malaysia and the Philippines subsequently rejected the new map while Indonesia insisted that the drawing of territorial lines must be in accordance with international laws. By the end of last year, China and the Philippines involved in a dispute on Scarborough Shoal where Chinese vessels blasted water cannons to prevent Filipino fishing vessels from reaching the shoal.

More recently, the more noticeable tension has been between China and the Philippines. The larger power was less than pleased when President Ferdinand Marcos Jr., who was elected in 2022, embraced closer ties with the U.S. During this past June's standoff which featured Chinese vessels engaged in ramming and towing of Filipino boats in the Spratly Islands’ Second Thomas Shoal, Washington warned that it’s obligated to defend Manila in any major conflict with an external actor under a 1951 mutual defense treaty.

In March 2024, China and the Philippines involved in another incident at the shoal. The Philippines had grounded a World War II-era warship in 1999 and has maintained regular rotation and resupply missions to deliver supplies ever since, while China has deployed regular coast guard patrols since 2013. The shoal has been the spot of contention between the two, as China has sought to prevent the Philippines from resupplying the grounded vessel. Both countries stated that they were protecting their sovereignty.

However, it is important to remember the tribunal’s South China Sea in 2016 found that China’s nine-dash line were without legal claims. The International Permanent Arbitration in the Hague ruled in favor of the Philippines. The panel also concluded that Beijing does not have a right over the resources within the nine-dash line that covers almost the entire disputed waters. It also ruled that Spratly Islands are not islands in a legal sense, rather rocks or low tide elevations. (For example, Second Thomas Shoal is identified as a submerged reef.)

Beyond a regional issue

The SCS disputes have also become an issue affecting relations between the U.S., China and to certain extent, Washington’s western allies.

The future trajectory of the tensions very much depends on not only the level of commitment of the claimant countries to regional stability and its impact of global economy, but also America’s willingness to prioritise the issue amid the conflicts in Gaza and Ukraine.

President Biden was noticeably absent from the 26th ASEAN summit in Jakarta last September, which seemed to participants and observers to contradict Secretary of State Anthony Blinken’s statement that Washington’s long term focus remains in the Asian Pacific.

The rivalry between the U.S. and China is affecting ASEAN’s role in facilitating dialogue in order to seek for a solution. Additionally, the organization's centrality may be difficult to keep, since some member countries may be closer to Beijing than others. For example, Cambodia, a close ally to China, blocked a 2012 ASEAN consensus statement on the SCS and did so again four years later. There is no guarantee that this behavior will not be repeated in future deliberations, even as forging a consensus on what steps need to be taken to prevent further incidents becomes increasingly necessary. ASEAN members may also need to balance demands of great powers with their commitments to the organization.

NATO summit and Indo–Pacific

At the most recent NATO Summit in Washington, the alliance couldn’t ignore the Indo-Pacific issue. Despite the focus of discussion about issues within the member states, such as the election in France and United Kingdom, as well as the ongoing war in Ukraine, the alliance’s communique acknowledged that the Indo-Pacific developments have affected Euro-Atlantic security. This view was also reflected by incorporating the Indo-Pacific (IP-4) countries of Japan, South Korea, Australia and New Zealand, the third time they were invited to a summit.

The involvement of NATO members and allies in the region isn’t new. In 2021, Germany sent its first warship to Indo-Pacific region for the first time in 20 years to support other western countries and object to Beijing’s territorial claims. That same year, the British aircraft carrier HMS Queen Elizabeth, along with naval vessels from the U.S., Japan, Canada, New Zealand and the Netherlands, conducted combined exercise in the west Philippine sea.

Since the stability of the SCS waterways is related to prosperity in Europe, other NATO member states are expected in the future to engage more with the U.S. in the Indo-Pacific region via the conducting of freedom of navigation operations to send a message to China that challenging the rule-based order doesn’t only mean going against Washington, but also its western allies.

The tensions will continue to ebb and flow and likely between China and the Philippines with the Spratly Island chains being the focal point. China will likely continue to ignore the 2016 United Nations Convention on the Law of the Sea ruling and stick with the “indisputable sovereignty” since "ancient time” as the basis for its claims. ASEAN members will remain divided on their response to China’s more assertive moves and sooner or later have an impact on ASEAN’s centrality in dealing with regional security issues, including the SCS.

While the Vietnamese land reclamation brings more militarisation to the disputed waters, it is less likely to create serious tensions. Hanoi's move seems to be more about boosting its presence in the SCS amid the rising tensions.

De-escalation attempts through the expected legally binding document Code of Conduct of the South China Sea is less likely to be signed by both China and ASEAN members anytime soon.

The conflict is unlikely to be resolved, but conflict management is possible. Recently, China and the Philippines held talks, in which they agreed to defuse ongoing tensions. However, de-escalation is unlikely to be permanent.

China and the United States are likely to keep the status quo in the disputed waters in the near future, despite their intensified rivalry.