PRESIDENT FERDINAND MARCOS of the Philippines, who imposed martial law in the 1970s and built a personalized dictatorship, vowed in 1980 not to lift military rule after a terrorist attack. Martial law was for the good of the country, he declared, saying he would not “abandon the people to the unruly anarchy” of the attackers. A week ago, President Rodrigo Duterte of the Philippines threatened to impose martial law if necessary in his drive against drug users and dealers. “No one can stop me,” Mr. Duterte said. “My country transcends everything else, even the limitations.”

The similar tone of these statements — both claiming a higher calling for trampling democracy — is reason to ask: What the heck is going on in the Philippines? Mr. Duterte appears to be steering this democracy into the dark corners of authoritarianism and driving an important U.S. ally into the waiting arms of China and Russia. On Jan. 6, he visited a Russian warship docked at Manila and told the head of the Russian Pacific fleet: “We welcome our Russian friends. Anytime you want to dock here for anything, for play, for replenish supplies or maybe our ally to protect us.”

Mr. Duterte, who has unleashed the police and vigilantes in a brutal extrajudicial campaign against alleged drug users and dealers in which an estimated 6,000 people have been killed, made his threat to impose martial law in a speech in Davao City in the south, where he was mayor for more than two decades. If the drug campaign deteriorates into “something really very virulent, I will declare martial law,” he said. When referring to the “limitations,” he meant the post-Marcos 1987 Constitution, under which the president may declare martial law “in case of invasion or rebellion, when the public safety requires it,” for no longer than 60 days, with approval by Congress. There is no provision for declaring martial law to fight drug trafficking and use.

As has happened before, aides and allies attempted to backtrack after Mr. Duterte’s outburst. But there was no taking back the words; he was quoted accurately. Those who suffered through eight years of martial law under Mr. Marcos — when political opponents were imprisoned and tortured — heard Mr. Duterte’s threat quite clearly. Franklin Drilon, the president pro tempore of the Philippine Senate, told the New York Times, “The truth is, mere talk of martial law is enough to send chills to the spine of any Filipino.”

As well it should. The U.S.-Filipino alliance is important, but if the United States abandons support for democratic values, it will have no more claim on Filipino friendship for the long term than any other power that chooses to bid. In his confirmation hearing before the Senate Foreign Relations Committee, secretary of state nominee Rex Tillerson said he needed more “facts from the ground” before he could express an opinion on Mr. Duterte’s bloody campaign. The facts are increasingly, distressingly evident.