Thinking Beyond Politics


During a media briefing, Department of National Defense (DND) Secretary Delfin Lorenzana said that the time had arrived for the Mutual Defense Treaty (MDT) “to be revisited, given that its provisions were formulated in the early 1950s.”

“We believe it is time to sit down with our US counterparts and revisit the terms of our alliance. We are partners. We have deep historical ties. We must clearly define our roles and responsibilities when the need arises to be joined in arms,” he said.

Secretary Lorenzana and the defense establishment feared that the Philippines might be unnecessarily dragged into an armed confrontation between the US and China. The two major powers’ military activities in the South China Sea — for example, the Chinese construction and fortification of several artificial islands and the American Navy’s active exercise of freedom of navigation and overflights in the disputed waters — are proverbial powder kegs.

There are real anxieties within the DND and the Armed Forces of the Philippines (AFP) despite assurances by American officials that the MDT is an “iron-clad” commitment, which the US will honor, even in the contested islands in the South China Sea. The DND’s move to reassess the MDT was driven by uncertainties over what the US can bring to the table and what it expects from the AFP in case of an armed clash between the American and Chinese forces in the South China Sea.

In June 2011, Manila sought an unequivocal US commitment to its defense.

Philippine officials argued that an armed attack on its forces anywhere in the Pacific should trigger an automatic US armed response. According to the Philippine interpretation, the US security guarantee should not be confined to Philippine metropolitan territory but should also extend to its naval and air units in the South China Sea.

The 1951 MDT, unfortunately, does not specify a retaliatory armed response to external armed aggression. It only requires each signatory to consult each other and determine what armed action, if any, both would take.

US policy remains vague and ambiguous regarding the nature of its treaty commitment. It stops short of any reference to an automatic response if an armed conflict erupts in the South China Sea. Instead, it emphasizes the treaty’s diplomatic (rather than the military) deterrence. It argues that since the US is a treaty ally of the Philippines, China cannot simply assert that events in the South China Sea, including the contested islands, are not any of Washington’s business.

Interestingly, Secretary Lorenzana’s call for an MDT review coincided with the changing American position regarding the MDT. Washington maintains its neutrality over the sovereignty issue and ensures certain ambiguities on the MDT.

Recent US attitudes toward China, however, have become more critical as the Trump administration engaged this emergent power in a strategic competition. In President Donald Trump’s last full year as president, the US openly challenged China’s expansive claims in the South China Sea as it clarified that the MDT would obligate the US to honor its treaty commitments to the Philippines.

In late January this year, newly appointed Secretary of State Antony Blinken called his Philippine counterpart to reiterate the MDT’s implications for the security of the two countries, specifically in case of an armed attack against the Philippine armed forces, public vessels, or aircraft in the Pacific, which includes the South China Sea.

Two events signified the changing US position regarding the MDT. First, in March 2019, during his official visit to the Philippines, then-Secretary of State Michael Pompeo directly addressed Secretary Lorenzana’s concern about the MDT: “As the South China Sea is part of the Pacific; any armed attack on Philippine forces, aircraft or public vessels in the South China Sea will trigger mutual defense obligations under Article 4 of our mutual defense treaty.”

And then, on March 20, 2021, Secretary Lorenzana informed the Filipino nation about the presence of around 220 blue-hulled Chinese fishing vessels moored in line formation at Julian Felipe Reef (international name: Whitsun Reef). He issued a statement announcing that the Philippines is ready to defend its national sovereignty and protect the country’s marine resources.

Washington promptly announced its support to Manila. National Security Adviser Jake Sullivan called his Filipino counterpart, Hermogenes Esperon, to emphasize that Washington’s backed the Philippines and that the MDT was applicable to the area.

On April 9, US Secretary of State Antony J. Blinken called Foreign Secretary Teodoro Locsin, Jr. to express Washington’s concern over the massing of Chinese maritime militia vessels in the South China Sea, and, more importantly, to reaffirm the applicability of the 1951 MDT in the South China Sea. US Department of Defense Secretary Lloyd Austin called Secretary Lorenzana to say that the USS Theodore Roosevelt, along with the amphibious assault ship the USS Makin Island, was on its way to the South China Sea.

In a statement, however, President Duterte declined Washington’s offer of assistance. Instead, he expressed doubt that the Philippines could count on its ally in case of a full-blown conflict in the West Philippine Sea.

Nevertheless, the incident revealed that top Biden administration defense and foreign affairs officials worked effectively with their Filipino counterparts against China’s coercive attempt to control Whitsun Reef. They affirmed the MDT’s applicability in the South China Sea imbroglio.


Dr. Renato De Castro is a Trustee and Convenor of the National Security and East Asian Affairs Program of the Stratbase ADR Institute.