In a powerful address at the Shangri-La Dialogue defense summit in Southeast Asia, Philippine President Ferdinand Marcos Jr. outlined clear criteria for what would constitute as an act of war by China. The statement was made in reference to the escalating tensions surrounding the Second Thomas Shoal, a reef in the contentious South China Sea, where the Philippines maintain an outpost.

Despite a 2016 ruling by the United Nations favoring the Philippines, China continues to claim ownership over the territory and has engaged in aggressive behaviors towards Filipino vessels resupplying the outpost. Reports have highlighted incidents of water cannon fire and even ramming of a Filipino vessel.

President Marcos stressed that the situation would be "very, very close to what we define as an act of war" if the aggression resulted in the loss of a Filipino citizen's life. The Philippines and the United States share a mutual defense treaty dating back to the 1950s, which adds further significance to this statement.

China's actions around the Second Thomas Shoal have been dubbed as falling within the "gray zone," as it uses its Coast Guard rather than its Navy to intercept Filipino vessels. While these encounters have led to injuries sustained by Filipinos, no fatalities have been reported thus far.

The main concern now lies in the Philippines' definition of an act of war in contrast to harassment and the potential for sparking a conflict between the United States and China. President Marcos asserted that the killing of a Filipino citizen by Chinese forces would "almost certainly" be a red line.

This keynote address by President Marcos has provided a significant platform for the Philippines, highlighting the country's growing role in regional security. In recent times, Manila has strengthened security ties with Washington and other like-minded countries, including Japan and Australia.

The South China Sea issue serves as a unifying cause for the broader coalition the Philippines is a part of. According to Southeast Asia expert Greg Poling, this dispute resonates with not just U.S. allies and partners in the region, but even those outside of it. The South China Sea raises fundamental questions about international law, and the consensus among these allies and partners is that China is in the wrong.

As tensions continue to rise in the South China Sea, President Marcos' defined criteria for an act of war by China brings further clarity to the Philippines' stance. The international community will be closely monitoring these developments, as the delicate balance in the region remains on the brink.

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