Philippine Security Officials Eye Review of 1951 US Mutual Defense Treaty, Creation of ‘Defense Cooperation Agreement’ with Vietnam

In response to rising tensions in the South China Sea, Philippine security officials are exploring the possibility of broadening the definitions of key provisions in the 1951 Mutual Defense Treaty with the United States. Additionally, the Philippines is reportedly aiming to sign a defense cooperation agreement with Vietnam before the end of 2024 following the recent visit of Vietnamese Defense Chief Phan Van Giang to Manila. 

Broadening the Interpretations of the Mutual Defense Treaty

At the sidelines of the three-day military conference in Manila organized by the United States Indo-Pacific Command (INDOPACOM) from August 27 to 30, Philippine Defense Secretary Gilberto Teodoro disclosed that discussions are ongoing between the Philippines and the United States about the possibility of expanding the interpretations of the 1951 Mutual Defense Treaty (MDT), in response to China’s recent hostilities towards Philippine aircrafts and vessels. Secretary Teodoro underscored the importance of broadening the 73-year-old defense pact’s definitions to effectively respond to evolving challenges in the West Philippine Sea, where China has effectively been challenging the definitions of what an armed attack is.  

“We’re getting narrowed down by the definition of [an] armed attack, public vessel…and the public gets frustrated [with] that. So, I think we should broaden the scope of the [Mutual Defense Treaty] to face a dynamic and cunning adversary,” Secretary Teodoro said. 

The defense secretary added that the greatest risk lies in restricting operational boundaries, which contrasts with the actions of a potential aggressor who may seek to expand their own boundaries through force. “The Mutual Defense Treaty should be interpreted dynamically… And the biggest danger for us is to narrow down… our operational limitations, which is contrary, perhaps, to what a potential aggressor does when it expands.” 

While Secretary Teodoro initially refrained from mentioning China by name, he eventually identified China as the “biggest disruptor of peace” in the greater South China Sea area, following its recent provocative actions and escalating aggression in the contested waters. “I believe they’re not undeterrable because it’s just a question of getting a worldwide consensus as much as we can — a principle of mass public opinion worldwide. And secondly, for the Philippines, collaboratively and on our own, it’s to create enough deterrence militarily in order to give them pause that we are serious in protecting our sovereignty and we will fight for it,” the secretary added at the forum. 

Apart from Secretary Teodoro’s remarks, Philippine National Maritime Council Spokesperson Vice Admiral Alexander Lopez emphasized that a review of the MDT is long overdue since strategic dynamics in the region have significantly evolved in the last 70 years. “On our end, the Mutual Defense Treaty dates back to 1951. Since then, the strategic landscape has changed significantly. So, maybe it’s high time to review it now,” Vice Admiral Lopez said in a separate media interview in Malacañang on August 28. 

Both statements from Secretary Teodoro and Vice Admiral Lopez followed a tense month of confrontations between Philippine and Chinese vessels and aircraft at Escoda (Sabina) Shoal, which some security analysts now identify as a new flashpoint between China and the Philippines. Escoda Shoal lies roughly 67.3 kilometers from Ayungin (Second Thomas) Shoal, which used to be the stage for most skirmishes between the Philippines and China before a “provisional understanding” to de-escalate tensions was recently agreed to by both countries. Both maritime features are situated well within the Philippines’ Exclusive Economic Zone (EEZ). 

A Possible Vietnam Defense Cooperation Agreement

Meanwhile, the defense secretaries of fellow South China Sea claimants Vietnam and the Philippines met last August 30 with the aim of further deepening security and military relations this year. 

Vietnamese Defense Minister Phan Van Giang and Secretary Teodoro signed Letters of Intent to strengthen collaboration on disaster response and military medicine. They also agreed to address any disputes “peacefully” and within the framework of international law, alluding to the dispute each country has with China over territory in the South China Sea.  

Analysts note that this is a significant step for Vietnam and the Philippines in relation to maritime cooperation, following a recent agreement that the two countries struck between their respective Coast Guards. “The two sides shared the importance of maintaining peace, stability, safety, and freedom of navigation and aviation in the East Sea, also known as the West Philippine Sea or the South China Sea,” Defense Minister Giang said in a joint briefing.  

Both defense chiefs also reportedly agreed to sign a defense cooperation agreement before the end of the year,  according to Secretary Teodoro. While details of the defense pact are not yet disclosed, analysts note that the agreement will likely encompass joint military activities and may include provisions about the overlap of its claims in the West Philippine Sea. 

Several analysts have pointed out the differences between China’s relationships with Vietnam and the Philippines, especially over each country’s claims in the greater South China Sea. Vietnam also appears to experience less aggression from China despite having militarized larger features in the region. Some observers recently pointed out that Defense Minister Giang has remained neutral about the Philippines’ encounters with China and did not mention China nor its activities in the disputed waters, instead reaffirming their Four No’s policy on non-alignment. 

Nonetheless, increased maritime cooperation and further collective action between Vietnam and the Philippines has been seen as a positive thing, demonstrating that countries with conflicting claims in the South China Sea need not engage in aggression against each other.