Philippine and U.S troops unload medical supplies as they land at Cagayancillo in Palawan for their Community Health Education and training as part of the 2016 Balikatan Exercise on Sunday. Dante Diosina Jr., ABS-CBN News/file

MANILA – The Philippines’ initiative Tuesday to terminate its Visiting Forces Agreement with the United States spells consequences extending at least to the rest of Southeast Asia where Washington’s military presence somehow provides stability amid the prevailing geopolitical uncertainties, foreign observers said.

“Regional countries, in particular in Southeast Asia, would be closely watching this situation in a manner possibly reminiscent of what happened back in the early 1990s, when the American troops were pulling out of the Philippines after the basing rights lapsed,” Collin Koh, a Research Fellow at Singapore’s S. Rajaratnam School of International Studies, told ABS-CBN News by email.

“While this may not result in the same type of fears that the move could result in a strategic vacuum back in the 1990s, there’ll still be concerns about whether the abrogation of the VFA may adversely impact the U.S. military presence in the region.”

The VFA, forged in 1998, governs the conduct of American troops while in the Philippines. For decades, U.S. forces visit the Southeast Asian country to conduct joint exercises and training and humanitarian missions, sanctioned by Manila and Washington’s 1951 Mutual Defense Treaty.

“The termination of the VFA would have a negative, if not shattering impact on regional security in Southeast Asia. (The Association of Southeast Asian Nation) members publicly and privately count on a U.S. military presence to counter-balance China,” said Carl Thayer, a professor emeritus at the University of New South Wales, Canberra at the Australian Defense Force Academy.

In a separate email, Thayer said the scrapping of the deal “would lead to a marked reduction of U.S. military presence, especially in the South China/West Philippine Sea,” while “any rupture in Philippine-United States relations would also undermine ASEAN unity and ASEAN’s centrality in the region’s security architecture.”

“Irritants in Philippines-U.S. relations during the Obama administration led Duterte to absent himself from an ASEAN-US leaders’ meeting. Similarly, irritants this year led Duterte to decline an invitation to attend a special US-ASEAN Leaders’ Meeting in mid-March,” he said.

Early into his presidency in 2016, Rodrigo Duterte did not conceal his aversion towards the United States, citing a past incident in his home city of Davao in the southern Philippines where the US government allegedly spirited away an American bombing suspect. He also frowned at concerns raised by the US government over his governance style, including his harsh policy against illegal drug suspects and other criminals.

“The formal notification of termination of the VFA marks a significant departure from anti-American rhetoric, to action that could result in the abrogation of the Mutual Defense Treaty between the Philippines and the United States,” Thayer warned.

Koh has a different view, however, on the latter part of that remarks by Thayer. “I was hearing from more authoritative, knowledgeable sources that the scrapping of the VFA may not necessarily unravel the other key security arrangements with the U.S., such as the Mutual Defense Treaty,” said Koh, whose research interests cover naval affairs in the Indo-Pacific, focusing on Southeast Asia.

“I don’t envisage a total breakoff in bilateral military relations, given that the MDT remains intact,” Koh said.

The abrogation of the VFA may have technical implications on American troops in the Philippines, but it may not necessarily mean that bilateral military training and exchanges will be curtailed, Koh said.

Thayer said it removes “the legal basis for the temporary deployment of U.S. forces in the Philippines, including naval port visits.”

As Koh sees “a transitory period of reviewing” of the activities already lined up this year between the two countries’ militaries once the VFA is terminated, Thayer said “the knock-on effect would impact negatively on the professionalism of the Armed Forces of the Philippines and their interoperability with U.S. military forces.”

“The Philippines once again would be ‘an orphan’ in the region as it was in the early 1990s when the Philippines declined to renew leases for U.S. bases in the Philippines. The expulsion of the U.S. led to China’s occupation of Mischief Reef in 1995,” Thayer said.

Koh said the defense buildups of other Southeast Asian countries, their "defense and security arrangements with a more diversified pool of external parties, and the significant amount of interest by such countries as Australia, France, India, Japan and the United Kingdom to enhance military presence in the region” could provide “some compensatory effect on the VFA’s termination.”

The VFA is deemed terminated 180 days after the serving of notice.