There are a number.

And Donald Trump just announced his backing for one, extending a White House invitation to a serial killer.

Philippine President Rodrigo Duterte has been criticized by Amnesty International and the United Nations for engaging in extrajudicial killings — also known as murder.

But we need not trust these sources: Duterte himself admitted it.

In December, reminiscing about his days as Mayor of Davao, Duterte recalled, “I used to do it personally. Just to show to the guys [police] that if I can do it, why can’t you … And I’d go around in Davao with a motorcycle, with a big bike around, and I would just patrol the streets, looking for trouble … I was really looking for a confrontation so I could kill.”

In a 2015 television interview, Duterte admitted his links to the Davao death squad, which is responsible for killing over a thousand people in his hometown.

During his presidential campaign, he warned that if elected he would kill 100,000 nationwide. He’s now pursuing that goal.

At his final campaign rally, he laid out his plan: “Forget the laws on human rights. If I make it to the presidential palace, I will do just what I did as mayor. You drug pushers, hold-up men and do-nothings, you better go out. Because I’d kill you. I’ll dump all of you into Manila Bay, and fatten all the fish there.”

He hasn’t stopped inciting violence as president, “Hitler massacred three million Jews (sic). Now, there is three million drug addicts. I’d be happy to slaughter them,” Duterte said.

Duterte and Trump tend to frame the former’s long-time killing spree as a war on drugs. That doesn’t make it right. As a U.N. official put it, “Allegations of drug-trafficking offences should be judged in a court of law, not by gunmen on the streets.”

But Duterte’s murders are much more than a drug war.

As mayor, he encouraged people to report those they suspected of criminal activity to a local government office which then publicized the list, and not long after, most would be missing or dead.

Some of the killers were masked men, but Duterte also employs market-based incentives to turn police into killers. They’re paid a bounty for each person they kill, while arrests generate no extra income for officers.

And, as Amnesty International documented, Duterte is prosecuting a war on the poor and on children.

Duterte himself warned not just “drug pushers and hold up men,” but also “do-nothings” that he would kill them — and he has. Amnesty concluded that the majority of victims reside in the country’s poorest urban neighborhoods — not exactly the home of drug kingpins.

Scores of children have also been murdered. Some were targets, but the Philippine president dismissed the murder of other children as “collateral damage.”

And how has President Trump reacted to his killer counterpart?

After a December phone call, President Duterte claimed President Trump “was wishing me success in my campaign against the drug problem. He understood the way we are handling it and he said there is nothing wrong with protecting your country.”

Saturday, our president had what he called a “very friendly” telephone conversation with Duterte and actually honored him with an invitation to visit the White House.

How can the United States embark on such a policy?

Of course, President Trump has substantial business interests in the Philippines, where his partner in a soon-to-be-opened $150 million project was recently appointed to a position in Duterte’s government.

We can only hope that Trump’s support for Duterte arises from ignorance or venality; a feeling of affinity for the Philippine president would be far more frightening.

Mellman is President of The Mellman Group and has helped elect 30 U.S. senators, 12 governors and dozens of House members. Mell