Politicians lie. There’s nothing they do better or more predictably. But Australian politicians have the uncanny ability to surpass even the most cynical expectations of what the people in power will sink to. And all they have to do is start talking about refugees.

Take Peter Dutton’s latest monstrosity.

On Good Friday PNG soldiers – drunk, according to reports – sprayed up to 100 bullets into the Australian-run detention centre on Manus Island.

Dutton’s response was as vile as it was predictable. “There was an alleged incident where three asylum seekers were alleged to be leading a local five-year-old boy back toward the facility”, he told Sky News. “I think some of the local residents were quite angry about this particular incident and another alleged sexual assault.”

This alleged link was dismissed out of hand by PNG police. According to the Huffington Post, their accounts confirmed “Dutton had gotten several key details wrong. They confirmed a young local boy had been near the centre recently, but that this occurred around a week before the shooting; that the boy had approached the centre asking for food, and was not ‘led’ there; that there was no claims of any sexual abuse, and that the boy’s parents had made no formal complaint to police; that the boy was 10 years old, not five; and that police were not investigating any link between this incident and the shooting.”

In other words, Dutton made the whole thing up.

There is nothing new in this. For well over a decade asylum seekers have been slandered in a fashion that would make Donald Trump blush. Most notoriously, the children overboard scandal in 2001 saw the Immigration Minister Phillip Ruddock assert that refugees had thrown their own children into the ocean as a ploy to force the hand of the government.

On that occasion, the rest of the cabinet stepped in, including the prime minister John Howard, all to back Ruddock’s lie. When defence personnel told the government that a photograph being exhibited as supposed evidence of the refugees’ barbarity was in fact of a completely different boat, they were ignored. Six years later when Howard was in his final months in office he still persisted in the lie, claiming the refugees “irresponsibly sank the damn boat, which put their children in the water”.

Where would our politicians be without this sort of slander? Well for one it would be much more difficult to justify their own abuse of refugees, which goes far beyond what even Dutton’s warped mind could manufacture. Even British fascist Nigel Farage once said he couldn’t stomach Australia’s asylum policies, whose myriad crimes include the systematic abuse of hundreds of refugee children, and drowning of hundreds more with government foreknowledge, distress calls ignored, and boats actively sabotaged.

Beyond this, in demonising refugees so incessantly, the government creates a justification for its own extreme authoritarianism. For its ruthless border security regimen, copious expenditure on surveillance, means of repression, prison construction, drones, police, and so forth, the government needs to create a deeply dehumanised “other” to target. If in doing so politicians unleash some of the latent viciousness of our deeply inhumane society, for them so much the better.

That’s why while brutes like Dutton vomit racist bile over the political landscape, veils of silence still shroud the conditions on Manus Island and Nauru. The government may luck out in its deal to send the refugees to America, but there is not one person who will be pushed away who has not been scarred for life, and in the meantime conditions remain as miserable as ever, with at least 40 refugees contracting dengue fever in the last few days.

Dutton will presumably claim that this is a consequence of refugees practising germ warfare.