Donald Trump’s tone may be unprecedented in American politics, but his policies aren’t. Barack Obama restricted the movement of citizens from the seven Muslim countries that ended up on Trump’s travel ban list. The wall that Trump wants to build along the Mexican border is an extension of Bill Clinton’s Operation Gatekeeper. Trump’s rampaging deportation machine was bequeathed to him by previous administrations, including Obama’s. And Trump is hardly America’s first racist president.

Even his ‘shithole countries’ comment is not new. Associating certain countries and people with human waste and sewage has a considerable pedigree in the history of imperialism, from the 18th century to today. Katie Hopkins, writing in the Sun in 2015, described refugees from war-torn African and Middle Eastern countries as ‘cockroaches’. In 2007, the Columbus Dispatch (published in Ohio since 1871) ran a cartoon that depicted Iranians as cockroaches crawling out of a sewer. In 2003, Oriana Fallaci wrote that ‘the sons of Allah are multiplying like rats’ – another underground, sewer-dwelling species. In September 2015, the Daily Mail published a cartoon that showed rats crossing a border along with Muslim immigrants and refugees, disturbingly reminiscent of the Nazis’ anti-Semitic propaganda.

As Marcus Rediker says in The Slave Ship: A Human History, white slave-hunters in Africa in the early 18th century referred to the Africans they killed and failed to take on board ship as human ‘wastage’. Those who were taken on board were locked up below decks for days on end in accumulating excrement.

Pears soap ran an advertising campaign in the 19th century implying that blackness was something that could be scrubbed off the skin and washed down into the sewers. The notion that cleanness was related to whiteness was popular among advertisers; French companies had their own versions of it. And it still persists: Unilever has twice in recent years produced adverts that appeared to show black women turning white after using its Dove products.

The derogatory terminology isn’t exclusively racist: there’s a long history of white people using it of other white people, as Nancy Isenberg shows in White Trash: The 400-Year Untold History of Class in America. Richard Hakluyt argued in the 16th century that the ‘waste people’ of England belonged in the ‘waste land’ of North America.

According to Julia Kristeva, faeces, urine, vomit and other excreta repel us precisely because they are part of our bodies. They challenge the boundary between self and other that human subjectivity is founded on. You could say something similar applies to imperialism: the empire wants to imagine itself as clean and pure, but the mere existence of its victims challenges that self-image, exposing its hypocrisy. The rhetoric of repulsion follows: comparing people to cockroaches, rats and waste; calling their countries shitholes.

Trump’s language is a reminder of a not too distant past, when the Europeans and Americans who went uninvited to far-off lands didn’t see the need for rhetorical somersaults to disguise their true feelings about the invaded.