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ISSN 2816-1971

  • Andrea Chloe Wong

The Philippines’ Red Line: A Warning to China, A Signal to the US

Amidst China’s gray-zone activities, the Philippines has drawn the red line by which to invoke defense pact with the US.

Photo credits: Presidential Communications Office

The Second Thomas Shoal has recently become a site of repeated Chinese harassments against the Philippines in the South China Sea. While there were previous attempts to disrupt Philippine resupply missions to the rusting BRP Sierra Madre ship grounded in the area, it was only this year that Chinese forces blatantly demonstrated their coordinated and ruthless efforts to disrupt these missions. The Chinese Coast Guard blasted water cannons, engaged in dangerous maneuvers, and rammed Philippine vessels that incurred damages and injured crew members.

China has steadily increased its coercive “gray-zone” activities that result in tensions at sea. These activities are enabled by its superior maritime capabilities that can impose military costs in a conflict scenario without triggering war. Thus, China has since been emboldened to employ them more assertively. The frequency of these deliberate Chinese activities however has led to redefining “gray zone” as clearly illegal, coercive, aggressive, and deceptive.

While the Philippines has long displayed maximum tolerance at sea, it eventually became alarmed with China’s elevated maritime aggressions that caused injuries against Filipinos. It was because of the severity of such gray-zone incident that Philippine president Ferdinand Marcos Jr. warned China not to cross the red line. According to Marcos, “If a Filipino citizen is killed by a willful act, that is I think a very, very close to what we define as an act of war and therefore we will respond accordingly. And our treaty partners, I believe, also hold that same standard”. Interestingly, Marcos’ statement adds to US President Joe Biden’s “ironclad commitment” in defending the Philippines: “Any attack on Philippine aircraft, vessels or armed forces in the South China Sea would invoke our mutual defense treaty”.

Such red line essentially laid the grounds by which Marcos shall invoke the Philippines’ 1951 mutual defense treaty (MDT) with the US. Yet drawing the red line for the Philippines consequently raises important concerns regarding American response in the event of a conflict in the South China Sea. 

The question often raised is the extent of US military assistance in defending the Philippines. When asked how the US would respond should China cross the red line, US Secretary of Defense Lloyd Austin refused to speculate in detail, preferring to emphasize the US goal of making sure “we don't allow things to spiral out of control unnecessarily". But the risks of miscalculations in the South China Sea are real given Chinese constant provocations. Thus, in the event of an attack against the Philippines, how will the US defend it? To what extent will the US assist or defend the Philippines?

Another concern is the possibility of US controlling the military conflict. Given its superior maritime capabilities vis-à-vis the Philippines, the US has the upper hand in directing a possible conflict with China. With nine American military access sites in the Philippines at its disposal under the Enhanced Defense Cooperation Agreement (EDCA), the US can mobilize these facilities, as well as defense forces and technology in site, should tensions in the South China Sea occur. The risk is that American defense of the Philippines may snowball into a broader US-China conflict that will allow the US government to use its ally as the venue and justification for its military actions.

For decades, the US has pursued its strategic ambiguity regarding the conditions by which the mutual defense treaty will be invoked. Given the shared threat perceptions against China and the convergence of interests with the Philippines regarding the South China Sea, the US has been clearer and more definitive in its defense commitment. However, to actually follow through with its “ironclad” commitment is another matter as the US can further interpret the conditions by which the MDT is activated, as it contemplates on the military risks in going against China in defense of the Philippines.

For the Philippines, the red line has been drawn amidst China’s frequent and ruthless gray zone activities. But for Marcos, going to war with China is precisely “what we want to avoid." “We want to do everything we possibly can together with our partners and allies to avoid that situation. This is not poking the bear.” Moreover, the Philippines continues to take a more peaceful and diplomatic approach towards maritime issues with China, particularly in the Second Thomas Shoal. According to maritime law expert Jay Batongbacal: “What the President was trying to point out was – it was not the right time. We can’t just run to Big Brother every time we feel slighted”. 

Given the increasing maritime tensions with China, the Philippines has strategically moved closer to the US. Consequently, the MDT has likewise evolved from strategic ambiguity to a more definitive commitment between allied partners. Regardless of the potential concerns surrounding the possibility of invoking the MDT, the strong rhetoric of American defense for the Philippines and the clear red lines articulated by Marcos should signal to China to refrain from further raising tensions in the South China Sea. Ultimately, the goal for both countries is not to invoke the MDT in the first place and avoid going to war with China. 

DISCLAIMER: All views expressed are those of the writer and do not necessarily represent that of IIPA and this platform.


Andrea Chloe Wong has a PhD in Political Science from the University of Canterbury in New Zealand. She formerly served as a Senior Foreign Affairs Research Specialist at the Foreign Service Institute of the Department of Foreign Affairs Philippines.



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