Republicans must be reaching for their blood pressure tablets each time their President utters some new blasphemy against the bedrock philosophies of their party, routinely insisting that his words matter less than the deeds that follow. If it’s a Monday, he is going to pull out of Nafta, the free-trade treaty with Canada and Mexico. If it’s a Tuesday, he is not. Right now, it seems that he will not.

And so they pray, it will turn out with the cosying of Donald Trump with his counterpart from the Philippines, Rodrigo Duterte. Recently, they had a “friendly discussion” by phone which ended with Trump inviting him to Washington. The White House said the two men had discussed how Manila “is fighting very hard to rid its country of drugs”. That’s one way of putting it.

Since taking power, Duterte has unleashed a bloody war on his own citizenry that has given police and vigilante gangs free reign to terrorise whole neighbourhoods and conduct extrajudicial killings. It is a violent strategy that has already claimed the lives of an estimated 7,000 people. His actions have earned him the nickname “Duterte Harry”: he is now an international pariah. (By the by, he also once called Trump a “bigot” and Barack Obama “the son of a whore”).

It didn’t help when Trump mused during an interview with Bloomberg that Duterte, elected last year, can’t be all that bad because of his political prowess.

“You know, he’s very popular in the Philippines,” Trump said. “He has a very high approval rating in the Philippines.”

Duterte: 'Give me a terrorist and I'll eat their liver with salt and vinegar'

Perhaps even more preposterous was Trump’s suggestion last week that he would be “honoured” to meet with Kim Jong-Un, the keeper of the world’s last gulag prisons, to discuss his nukes.

“At a very young age, he was able to assume power,“ he said of Kim, almost flatteringly. ”A lot of people, I'm sure, tried to take that power away, whether it was his uncle or anybody else. And he was able to do it. So obviously, he's a pretty smart cookie.”

Is this further proof of Trump having the warm and fuzzies for strongmen dictators? Recall his admiring words for Vladimir Putin last year and the welcome he extended last month to the Egyptian President, Abdel Fattah el-Sisi, on his first visit to Washington since seizing power in a coup four years ago.

Then there was his congratulatory call to Turkish President, Recep Tayyip Erdogan, after he won a referendum last month, allowing him further to tighten his grip on power.

Who knows what drives Trump, sometimes? We may not be able to guess what he’s thinking. We can talk, however, about the damage he is doing to America’s reputation for pursuing – though not consistently, it’s true – a foreign policy underpinned by respect for human rights, freedom and democracy.

Call it the doctrine of Woodrow Wilson, if you like, or of Franklin Roosevelt, who, after no little hesitation, came to the assistance of the allies against Hitler, or indeed of Ronald Reagan, whose call to Gorbachev to “tear down this wall” helped propel the collapse of the Soviet Union.

Trump seems not to care about any of that. “We are watching in real time as the American human rights bully pulpit disintegrates into ash,“ Chris Murphy, a Democratic Senator, observed in a Twitter message after hearing Trump’s Duterte and Kim musings.

Most affronted, though, are those Republicans who believe their party still belongs to Reagan (or, at least, it should).

“This is a dramatic departure,” Senator John McCain told MSNBC, citing Reagan. “We are proud Republicans and we stand for human rights. The statements, and the comments, obviously fly in the face of everything that I’ve stood for and believed in all my life.” The senator, who recently dined with Trump and insists he wants to help him, also warned that praising the likes of Duterte will have consequences. “I don’t think that the President appreciates the fact that when he says things like that it helps the credibility and the prestige of this really outrageous strongman. You can’t praise that kind of behaviour and not raise concerns around the world.”

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What should worry McCain is that Trump has company in his administration de-emphasising human rights in global relations. It is not NAFTA bluster: there one day, gone the next. Last week saw Rex Tillerson, his Secretary of State, using a pep talk to diplomats in the State Department auditorium to explain precisely why America has been too concerned about propagating American values overseas when it really should be worried first about protecting national interests. It’s the foreign policy expression of Trump’s over-arching “America First” proposition.

“It is really important that all of us understand the difference between policy and values,” he lectured. “Our values around freedom, human dignity, the way people are treated – those are our values. Those are not our policies. In some circumstances, if you condition our national security efforts on someone adopting our values, we probably can’t achieve our national security goals.”

No one could argue that America has always put human rights or democratic freedoms at the heart of all its foreign policy actions: the joining of hands by the allies with Stalin against Hitler is perhaps the clearest example of its failure to do so. Churchill famously explained it thus: “If Hitler invaded hell, I would make at least a favourable reference to the devil in the House of Commons.” Sometimes, needs must. It’s also true that America’s aversion to tyrants hasn’t always worked out so well. Think Saddam.

But Washington explicitly de-emphasising the proliferation of its values across the board of foreign policy is a profound and unnerving shift. America is the country most able to punish those who subjugate or terrorise their own populations. If it steps back, bullies worldwide will be emboldened. Moreover, the argument can still be made that America’s national security, as well as its trade and economic interests, are precisely advanced by encouraging others to adopt its values. “Divorcing our interests from our values in foreign policy is like trying to plant cut flowers,” John Kirby, a former State Department spokesman, noted despairingly.