By Vanne Elaine Terrazola Two senators said President Duterte has all the authority to terminate the Philippines' Visiting Forces Agreement (VFA) with the United States, especially if the latter has been interfering in the country's internal affairs. (L-R) Sen. Aquilino "Koko" Pimentel and Sen. Vicente Sotto III (MANILA BULLETIN) Senate President Vicente Sotto III appeared to support Duterte's threat to scrap the VFA after the US cancelled the 10-year, multiple entry visa of Sen. Ronald "Bato" dela Rosa, one of the President’s closest allies. Dela Rosa was Duterte's former Philippine National Police (PNP) chief and the main implementor of his war on drugs from 2016 to 2018. Some US officials have criticized the campaign for the alleged killings and human rights violations committed by law enforcement agencies. READ MORE: ‘Birthday gift’: Sen. Bato confirms his US visa has been canceled In his speech Thursday night, Duterte said he is giving the US one month to "correct" the visa cancellation and warned he would kick American troops out of the country if it fails to do so. "Perhaps this action can make the US Senate rethink their wrong perception about our justice system. He is the President, the buck stops with him," Sotto said in a text message. As to how the threat will affect the Philippines and US relations, Sotto said, "It depends on how important they view US as an ally. The question is...Why are they so obsessed about our fight against drugs? Palibhasa ba dahil hindi nila ma-solve 'yong kanila (Because they can't solve their own problem)?" Sen. Aquilino "Koko" Pimentel III said Duterte, as the country's chief foreign policy architect and the commander-in-chief of the Armed Forces of the Philippines, can terminate the VFA if he wishes to. He said he also understood the President’s reason for issuing the threat. "The reason stated by the president for terminating the PH-US VFA may sound 'personal' but I see the point of the President," Pimentel said in a text message to the Manila Bulletin Friday. "He believes Sen. Bato is being punished by the US for having once been the implementor of his main program of government -- the all-out war against drugs. Since that is domestic policy, then punishing someone, even if indirectly, for a domestic policy shows the intent to interfere by a foreign state with domestic policy," the Duterte ally added. The lawyer and current chairman of the Senate committee on foreign relations likewise stressed that foreign military bases are prohibited in the Philippines under the Constitution. He referred to Article 18, Section 25 of the 1987 Constitution, which states that "foreign military bases, troops, or facilities shall not be allowed in the Philippines except under a treaty duly concurred in by the Senate and, when the Congress so requires, ratified by a majority of the votes cast by the people in a national referendum held for that purpose, and recognized as a treaty by the other contracting State." "Having a foreign armed force inside a sovereign nation like the is an 'unnatural' situation. That is why our constitution provides strict requirements before a foreign armed force can be stationed here: it must be under a treaty and the other state must treat the agreement as a treaty too," Pimentel said. The VFA entered into by the Philippines and the US in 1998 stipulates how the Philippines should treat American military personnel while in the country. Under the agreement, American military personnel are exempted from passport and visa regulations when entering and departing the Philippines. Their US-issued driving permits and licenses shall also be accepted as valid in the Philippines. The deal also laid out the jurisdiction of the Philippines and the US when American military personnel commit crimes here. It also waives landing or port charges for vehicles, vessels, and aircraft operated by or for the United States armed forces while in the Philippines. Either the Philippines or the US can terminate the VFA if they desire so. While the Constitution required the Senate's concurrence in entering into treaties with other countries, it was silent on whether or not the chamber's approval is needed to terminate such agreements. Sotto said the Senate would discuss this if President Duterte sends them a correspondence. READ MORE: Duterte turns down Trump’s invite; termination of VFA starts "We shall deal with it as a body. The President is the architect of our foreign policy but we in the Senate participate in treaty making," he told the Manila Bulletin. Senators Franklin Drilon and Panfilo Lacson agreed on Friday that President Duterte can terminate the VFA without their consent. READ MORE: Duterte may terminate VFA on his own – Drilon, Lacson