IT was the kind of publicity money can’t buy – and in the world of US politics, nothing comes cheap. When four congresswomen gathered around a lectern on Monday to respond to the latest extraordinary outburst by Donald Trump, the resulting photographs, beamed across the world, looked like stills from the next series of Madam Secretary or The Good Fight.

Hollywood lighting makes the President of the United States look like he’s been exfoliating with Wotsits, but here it bathed Alexandria Ocasio-Cortez in an ethereal glow as she calmly responded to the suggestion she should “go back” to the country she “originally came from”.

She had a message for the children of the nation that “no matter what the president says, this country belongs to you, and it belongs to everyone”. Her colleague Ayanna Pressley had already firmly cautioned “do not take the bait”, and all four agreed that the president’s latest rant was nothing but a fresh distraction from domestic challenges such as sky-high healthcare costs, relentless gun violence and widening wealth inequality.

One might hope that American citizens – regardless of their political affiliations – would take the view that this time Trump had gone too far. That the president of this nation of immigrants simply should not be able to get away with such blatantly racist conduct.

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But no. Opinion polls carried out in the last few days have in fact found his approval rating has jumped by five percentage points among Republican Party supporters. Depressingly, it appears that in the land of the free and the home of the brave, the overt and sustained bullying of female politicians of colour is political currency. While Trump might give the appearance of a loose cannon, he knows exactly what he’s doing.

The National: Donald Trump put the focus on Congresswoman Ilhan Omar during a rally in North CarolinaDonald Trump put the focus on Congresswoman Ilhan Omar during a rally in North Carolina

The country where Ocasio-Cortez, Pressley and their colleague Rashida Tlaib “came from” is the United States of America. Ilhan Omar was born in Somalia, her family claimed asylum when she was 10 years old and she became a US citizen in her teens. But let’s be honest – these details matter not one jot to the audience Trump was targeting when he fired off his tweets at the weekend.

Those voters only need to glance at the photographs of those four brown-skinned politicians to understand what is meant by “going back”. They are not concerned about having a racist in the White House – on the contrary, they are pleased about it. As the polls show, they actively approve.

Trump himself is, of course, the son of immigrants, and for the record we don’t want him “back”. He claims the left-wing women known informally as “The Squad” originally came from “countries whose governments are a complete and total catastrophe, the worst, most corrupt and inept anywhere in the world” – and as letter-writer Harry Key pointed out in yesterday’s National, he’s actually not far wrong. On Wednesday the House of Representatives (including a handful of Republicans) voted to condemn Trump for making “racist comments that have legitimised fear and hatred of New Americans and people of colour”, but this is just the latest footnote in an ongoing catastrophe that has seen the US slide backwards into protectionism and nepotism, with the legitimisation at the highest level of sexism, racism and pretty much every negative -ism in the dictionary.

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Trump accused the quartet of politicians of “spewing some of the most vile, hateful and disgusting things ever said by a politician”, shortly before standing on the White House lawn and saying of Omar, the first naturalised citizen from Africa to serve in Congress: “Well, there’s a lot of talk about the fact that she was married to her brother ... I don’t know, but I’m sure that somebody would be looking at that.”

Hours later he again took aim at the same congresswoman during a rally in North Carolina, and the crowd responded with its appalling chant of “send her back”. When his aide Kellyanne Conway was asked which countries the president meant when he suggested the four congresswomen return to them, astonishingly she managed to make matters even worse, by asking a reporter “what’s your ethnicity?”

Nothing about the Trump presidency should surprise us these days, and certainly not when it comes to the special brand of aggression he reserves for women. “Send her back” is the new “lock her up”, and it’s no coincidence that the man who boasted about grabbing women by their genitals is egging on his supporters to chant about female politicians in particular.

But what’s particularly galling is his attempt to smear their characters, rather than address their policies. Michelle Obama may have once urged Democratic Party supporters “when they go low, we go high”, but surely only a saint could stay quiet when having their character assassinated by a man who stands accused of raping, groping or otherwise sexually assaulting 22 women; is the subject of a wide-ranging investigation into alleged obstruction of justice, corruption and abuse of power; and was brought to power by a bunch of criminals.

Tempting as it may be for these women to hit back with reminders of just how awful a person the current President of the United States really is, sadly such a response feels futile. The voters already know; enough of them just don’t care.