Last week's clash between Chinese and Philippine forces in the South China Sea left several injured, raising the specter of a future scenario that could trigger the U.S.-Philippine Mutual Defense Treaty (MDT) and spark a great power conflict.
Article V of the 1951 treaty states one partner would be obliged to come to the other's aid in the event of an "armed attack on a metropolitan territory of either of the parties or on the Island territories under its jurisdiction in the Pacific Ocean, its armed forces, public vessels or aircraft in the Pacific."
President Joe Biden has stressed the U.S.' commitment to the treaty on multiple occasions, including during Philippine President Ferdinand Marcos Jr.'s visit to the U.S. in April.
However, what is considered as constituting an "armed attack" in Washington and Manila is unclear.
The Marcos administration's pushback against Beijing's territorial claims has been met with a Chinese willingness to use non-deadly force, including water cannons, up-close maneuvers that risk collision, and alleged high-powered laser and sonic devices.
Beijing asserts sovereignty over nearly all of the South China Sea, through which over $3 trillion-worth of trade is estimated to pass each year.
These claims include areas falling within the exclusive economic zones of the Philippines and several other Chinese neighbors. An international court in 2016 largely dismissed China's claims, but Beijing has called the ruling politically motivated and invalid.
Philippine sailors were injured in March when a Chinese water cannon shattered the windshield of a government-commissioned boat carrying supplies to Second Thomas Shoal, a contentious South China Sea reef where Manila stations a small contingent of marines aboard grounded warship the BRP Sierra Madre.
Chinese maritime forces reportedly intercepted Philippine boats on a supply mission to Second Thomas Shoal on June 17.
Several Philippine troops were injured, including one who lost his thumb in a collision with a Chinese boat. Chinese Coast Guard personnel brandished knives, sticks and an axe, Manila said.
China's Foreign Ministry said the Philippine boats had been trespassing in an attempt to secretly deliver construction supplies to reinforce the Sierra Madre. The Chinese Coast Guard took "necessary control measures in accordance with the law," the ministry added.
"I believe that Manila would be perfectly justified in invoking the MDT now," Ray Powell, director of the Stanford University-affiliated SeaLight initiative, told Newsweek. He said it could start with Article III of the document, "due to the very real threat to the Philippines' territorial integrity and national security."
Article III calls for consultations on the treaty's implementation "whenever the territorial integrity, political independence, or security" is believed to be under threat by armed attack in the Pacific.
"This would have a very helpful and clarifying effect on Manila's understanding of America's willingness to get involved; Washington's understanding of the Philippines' needs, expectations and intentions; and Beijing's concept of how serious its escalations have allowed this situation to become," Powell added.
Collin Koh, a maritime security expert at the S. Rajaratnam School of International Studies in Singapore, previously told Newsweek a precedent was set when the treaty wasn't invoked the first time a water cannon attack resulted in injuries to Philippine personnel.
"I believe Beijing senses impunity to keep doing the same," he said. "So we can expect recurring situations like this, which may even potentially result in fatalities or at least more serious injuries if Manila and Washington don't revisit the premises and assumptions underpinning the MDT."
Marcos signaled what would likely be a "red line" in May.
He stressed that if a "willful act" causes the death of a Philippine citizen, "we would certainly have crossed the Rubicon," adding that Manila and its partners would respond to such a scenario with "joint action."
Marcos in April cited U.S. Secretary of State Lloyd Austin as saying Washington would also regard this as the threshold for invoking the treaty.
In a speech to troops on Sunday, however, Marcos said the Philippines is "not in the business to instigate wars" and said his government would not adhere to "rules that force us to choose sides in a great power competition."
The Southeast Asian country is now working to resume talks with China on the territorial dispute.
The nation's top diplomat, Enrique Manalo, told legislators Tuesday that a joint China-Philippine working group held a meeting last week with the aim of setting up a bilateral dialogue in July.
"Whatever confidence-building measures we achieve, they will be not at the expense of promotion of our sovereignty, sovereign rights, as well as our rights and jurisdiction on the West Philippine Sea," he added, using Manila's term for South China Sea waters within the country's exclusive economic zone.
The Philippine Department of Foreign Affairs and Chinese foreign ministry didn't immediately respond to written requests for comment.
About the writer
Micah McCartney is a reporter for Newsweek based in Taipei, Taiwan. He covers U.S.-China relations, East Asian and Southeast Asian ... Read more
