MANILA – Philippine President Rodrigo Duterte’s decision to scrap a key security pact with the United States will be challenged at the nation’s highest court, a legal maneuever that could have major implications for regional security and balance of power politics.

In a rare bipartisan move, the Senate’s majority and minority leaders petitioned the Supreme Court to rule on the legality of Duterte’s unilateral abrogation of the Visiting Forces Agreement (VFA), which provides a legal framework for the rotational stationing of US troops and equipment on Philippine soil.

Duterte’s cancellation of the 20-year-old pact, which is scheduled to take effect on August 9, threatens to undermine the legal standing of the two sides’ 1951 Mutual Defense Treaty (MDT) and will inevitably hamper the US’s strategic position vis-à-vis China, most notably in the hotly contested South China Sea.

The petition, which seeks a ruling on the limits of the president’s executive powers, is supported by a majority of senators apart from a clutch of Duterte’s closest allies. It was filed jointly by Senate President Vicente Sotto III, Senate Pro Tempore Ralph Recto, Majority Leader Juan Miguel Zubiri and Minority Leader Franklin Drilon.

It has also received the backing of senior senators Richard Gordon and Panfilo Lacson, who lead key committees related to security in the legislature’s upper chamber. Both senators have already rang alarm bells over Chinese “infiltration” and “immersion operations” that seek to take advantage of US troop withdrawal.

The Senate’s petition maintains that any abrogation of a ratified international treaty that has been incorporated into domestic law must under the constitution also be approved by the the legislature’s upper house.

Duterte, the petition says, did not consult the Senate in making what amounted to a unilateral decision.

Philippine President Rodrigo Duterte (L) talks to US President Donald Trump (R) at the ASEAN Summit in Manila, November 13, 2017. Photo: AFP/Pool/Mark R Cristino

The move has been widely perceived as a tit-for-tat response to US travel bans imposed against certain of Duterte’s top allies responsible for prosecuting his controversial drug war.

The president’s spokespeople have said that the VFA’s abrogation was well-deliberated and not a knee-jerk decision, as Duterte’s critics in Congress have claimed.

Analysts now wonder whether the country’s highest court, known for being packed with Duterte’s schoolmates and loyal appointees, will rule on the legal merits of the case and dare to overturn such a high stakes executive decision.

Though Duterte has repeatedly reiterated his commitment to terminating the VFA, his spokesman Salvador Panelo has indicated that the government would abide by any Supreme Court ruling.

In their petition, senators have specifically asked the high court to clarify the precise extent of presidential powers on abrogating international treaties that have been ratified by the Senate, including specifically the VFA.

The legislators have cited two relevant provisions in the Philippine constitution, namely relevant articles in the charter’s sections 21 and 25, which many legal experts believe require Senate concurrence on matters related to international treaties.

The senators have said that their petition does not intend “to undermine the president’s prerogative to implement an “independent foreign policy”, but rather “merely seeks to subject the notice of withdrawal to proper deliberative process by the Senate.”

They also argue that since any treaty is already part of domestic law, the VFA and by extension other treaties, are a matter of legislation which “requires concurrent acts of the president and the Senate.”

US and Philippine Marines carry their respective colors at the formal opening of the annual Philippine-US Amphibious Landing Exercises aboard the USS Bonhomme Richard, October 8, 2012. Photo: AFP/Jay Directo

The Duterte administration, for its part, maintains that the constitution is silent on matters of withdrawal from treaties, with Senate concurrence required only when the Philippines is acceding to one.

“Under our laws and constitution, the chief architect of foreign policy is President Rodrigo Duterte and not any interloper who probably wants to be president,” the government’s chief lawyer, Solicitor General Jose Calida, told CNN Philippines last year.

Analysts and observers see three likely outcomes of the Senate’s legal challenge.

First, the Supreme Court’s judges could drag their feet on the matter, as they have on an earlier petition filed by opposition senators who challenged Duterte’s unilateral withdrawal from the International Criminal Court (ICC) in 2018.

This way, they say, the high court can avoid confrontation with both sides while allowing the VFA’s termination to take legal effect in August.

In a second scenario, a majority of Supreme Court justices can question the nature of the VFA, arguing that the pact is fundamentally an executive agreement, as opposed to the 1951 Mutual Defense Treaty, since the US Senate has never ratified it.

It is thus entirely within Duterte’s powers to preserve or abrogate the agreement as a matter of executive prerogative, such a ruling could say.

Student activists in the Philippines protest against both China and the United States equally in a file photo. Photo: Facebook

In a third scenario, the high court could try to split the difference by handing both the president and Senate a partial victory.

That is, the Supreme Court could rule in favor of Duterte’s withdrawal from the ICC, a matter that cuts closer to Duterte with impending international probes into alleged widespread extrajudicial killings in his lethal drug war.

The high court, which ruled previously in favor of other major defense deals and arrangements with the US, could then adjudicate in line with the Senate on the VFA without causing Duterte to lose much face.

Duterte, who has repeatedly warned the high court against interfering in executive affairs, has remained adamant about his decision to abrogate the VFA.

In response to the senators’ petition, Duterte, a lawyer by training, exclaimed: “They cannot compel me. I refuse to be compelled. I have terminated it.”

Despite that tough talk and political posturing, Duterte may actually welcome a ruling in favor of the Senate’s petition, some analysts believe.

If successful, the Senate’s challenge could provide Duterte with an opportunity to de-escalate tensions with the US and avoid confrontation with key members of the Philippine defense and security establishment who prefer to retain the VFA.

A Philippine naval officer stands guard during the arrival of American missile destroyer USS Chung Hoon before US-Philippine joint naval military exercises in a file photo. Photo: AFP/Noel Celis/Getty Images

Moreover, it would allow Duterte to portray the Philippines as a functioning democracy, with his administration ostensibly respectful of rule by law and the separation of powers among the executive, legislature and judiciary.

Either way, Duterte could claim a populist victory by dropping the gauntlet on the Philippines’ ex-colonial ruler and top security partner for interfering in the country’s internal affairs, only to back down in deference to a Supreme Court ruling.

Indeed, presidential spokesman Panelo hinted as much last month when saying, “We will follow the Supreme Court. Whatever the law says, we will follow.”