EXPLAINER: The PH-US Mutual Defense Treaty

President Ferdinand “Bongbong” Marcos Jr. said the latest water cannon attack by China against a Philippine boat near Ayungin Shoal, where four Filipino Navy personnel were hurt, is not enough to invoke the Mutual Defense Treaty (MDT) with the United States.

“I do not think that it is a time or the reason to invoke the Mutual Defense Treaty,” Marcos said in a video message.

But the question is why?

When will the Philippines invoke the MDT with the US against the aggression of China in the West Philippine Sea (WPS)?

The MDT

Signed by Manila and Washington in 1951, the MDT is a defense pact that unites the two allies to help defend each other from aggression.

Under Article IV of the treaty, it is stated that the Philippines and the US recognize that an armed attack in the Pacific area on either of them would be dangerous to their respective peace and safety.

The two countries also declared that they would act to meet the common dangers in accordance with their constitutional processes.

Under Article V, it is determined that the treaty covers an armed attack on the metropolitan territory of either of the parties, or on the island territories under its jurisdiction in the Pacific Ocean, or on their armed forces, public vessels, or aircraft in the Pacific.

March 5 Ayungin Shoal incident

In the March 5 incident, the Armed Forces of the Philippines (AFP) deployed two civilian boats to conduct a resupply mission to BRP Sierra Madre grounded at Ayungin Shoal.

Two Chinese Coast Guard (CCG) vessels water cannoned one of the Philippine boats, Unaizah May 4, shattering its windscreen and injuring four Filipino Navy personnel on board.

Maritime law expert Jay Batongbacal told GMA News Online that China’s water cannon attack that hurt Filipino military men does not fall under Article IV of the treaty.

“Technically no; ‘armed attack’ contemplates use of military force and a certain degree and scale of violence that is not specifically defined; but is not likely to cover this incident where one vessel suffered damage and slight injury,” he said.

“The MDT qualifies that the armed attack should be ‘dangerous to its (i.e., the State's) own peace and safety’; one incident will not create this situation,” he added.

Batongbacal, director of the University of the Philippines Institute for Maritime Affairs and Law of the Sea, also noted that Article IV does not specify what response will be taken.

Gray zone tactics

In China's December 2023 water cannon attack, AFP chief General Romeo Brawner Jr. had said that it was not yet the time to invoke the MDT with the US as "water cannoning is not considered an armed attack."

Brawner had pointed out that China engages in "gray zone tactics.”

Gray zone is “an effort or series of efforts beyond steady-state deterrence and assurance that attempts to achieve one’s security objectives without resorting to direct and sizable use of force,” as defined by the National Defense College of the Philippines.

“In engaging in a gray zone strategy, an actor seeks to avoid crossing a threshold that results in war," it added.

China has been engaging in shadowing, blocking, performing dangerous maneuvers, and even laser pointing against the Philippines in the WPS.

Philippine Coast Guard releases videos showing China Coast Guard's “dangerous maneuvers” and “illegal use of water cannons” against PCG vessels going to Ayungin Shoal on August 5. Videos: PCG @gmanews pic.twitter.com/VgY2EYrtX1

— Joviland Rita (@jovilandxrita) August 7, 2023

Triggers

While both of the countries require constitutional processes to invoke the MDT, Batongbacal said the US has more flexibility than the Philippines because the former has the War Powers Act.

“The US is in fact more flexible than the Philippines, due to the War Powers Act which allows the US President to commit US forces to engage in armed conflict for at least 60 days subject only to reporting to Congress,” he said.

“The Philippines does not have similar rules and only says that the Philippine President can call out the armed forces in case there is a state of lawlessness, violence, invasion, or rebellion,” he added.

Two scenarios are possible that could trigger the MDT in the WPS, foreign policy expert Aaron Jed Rabena said in his article published on Asia Maritime Transparency Initiative in 2019.

These are an armed attack on the Philippines or on the US by a third party, according to Rabena, who is a research fellow at the foreign policy think tank Asia-Pacific Pathways to Progress.

In the US, the President can only tap its military if there is either a declaration of war by Congress, existence of a national emergency, or a statutory authorization by virtue of the War Powers Act, he said.

In the Philippines, Rabena said the Constitution allows the Congress to declare a state of war. In this condition or during a national emergency, the President has the power “to carry out a declared national policy.”

Rebena noted that despite the congressional restriction, there were instances when the Philippines previously gave assistance to the US even without a declaration of war. 

Ironclad

Following the March 5 incident in Ayungin, the US reaffirmed the MDT with the Philippines. 

"The United States reaffirms that Article IV of the 1951 US-Philippines Mutual Defense Treaty extends to armed attacks on Philippine armed forces, public vessels, or aircraft—including those of its Coast Guard—anywhere in the South China Sea," said State Department spokesperson Matthew Miller.

A few months later, US President Joe Biden also declared that the country's defense commitment to the Philippines is "ironclad."

"Any attack on Filipino aircraft, vessels or armed forces will invoke our mutual defense treaty with the Philippines," Biden told reporters back in October.

"I want to be very clear," he said. "The United States defense commitment to the Philippines is ironclad." 

Claims

Tensions between China and the Philippines have heightened in recent months as both sides trade accusations over a series of incidents in the WPS.

China claims almost the entire South China Sea, a conduit for more than $3 trillion in annual ship commerce. Its territorial claims overlap with those of the Philippines, Vietnam, Malaysia and Brunei.

Parts of the waters within the Philippines' exclusive economic zone have been renamed as West Philippine Sea.

In 2016, an international arbitration tribunal in the Hague said China's claims had no legal basis, a decision Beijing has rejected. 

On Thursday, China's President Xi Jinping on called on its armed forces to coordinate preparations for military conflicts at sea, protect the country's maritime rights and interests and the development of the maritime economy. —VAL/KBK, GMA Integrated News