On 9 October, 2012 Prime Minister Julia Gillard famously stood up in parliament to accuse Leader of the Opposition Tony Abbott of misogyny and sexism. Though he may not have known it at the time, he was the victim of a reverse dog whistle (RDW). It didn’t seem to hurt his career; he went on to become PM himself less than a year later. But Gillard’s RDW was heard as far away as Washington, where Hillary Clinton agreed that Gillard faced ‘outrageous sexism’. Whistles carry in the thin air of identity politics.

A few years later, in 2015, the United Nations special rapporteur on the rights of indigenous peoples, Victoria Tauli-Corpuz, accused then-PM Abbott of making ‘racist kinds of pronouncements’ about Aboriginal Australians for suggesting that the government should not provide unlimited funds for remote communities. Racism charges were renewed when Abbott suggested that indigenous Australians are better off for being, well, Australian. Chalk up two more RDWs.

Tony Abbott isn’t the only one who gets RDW’d, but he gets it a lot. Alan Jones is another frequent target of the RDW, as are Israel and the Catholic Church. Spectator columnists get RDW’d all the time, and British ‘leave’ voters have been RDW’d en masse. Anti-Trump hysteria is a shrill sewer of RDWs – but don’t call it ‘hysteria’, or you risk being RDW’d yourself. Only sexists say ‘hysteria’, which derives from the Greek root hister (womb), implying that it is a specifically female affliction.

When actual racists want to disparage their victims while staying within the bounds of polite speech and Section 18C, they can ‘dog whistle’ their insults in terms that only fellow racists fully understand. For example, in the United States, ‘welfare queen’ is a racist dog whistle for African-American single mothers in Northern cities. Down south, ‘states’ rights’ has long been the favoured dog whistle for segregation.

Both are successful as dog whistles because it is outwardly reasonable to support tighter controls on welfare recipients, or to advocate localism in political decision-making. Racists use these terms to signal to each other without getting kicked off the major TV networks or exiled from the opinion pages of the big city dailies.

Whereas the conventional dog whistle is a secret code for reaching out to your own racist supporters, the reverse dog whistle is a secret code for driving away your opponent’s perfectly respectable supporters. The conventional dog whistle is a polite way of saying ‘I’m not allowed to say it, but deep down I’m really one of you’. The reverse dog whistle is an extraordinarily impolite way of saying ‘if you support this person, you must be a racist’.

A racist, or a sexist, or a fill-in-the-blank-o-phobe: Speccie contributor Christopher Akehurst’s ‘three little words’. Akenhurst thinks they’re used to shut people up, but the kinds of people who get RDW’d are the kinds of people who go right ahead loudmouthing their messages to the world no matter what people say about them. The reverse dog whistle isn’t used to shame public figures into abandoning the causes they believe in. It’s used to drive away their less-pugnacious supporters.

The RDW has sanitised mainstream political debate to the point of irrelevance. Important political issues, often the issues that matter most to ordinary voters, have been pushed to the marginal arenas of online commentary and late night cable television. Bold figures with big egos still take on issues like trade, immigration, wages, housing, energy prices, school curricula and electoral reform, but the mainstream media does its best to ignore them. Experienced rabble-rousers may not be afraid of being RDW’d, but their advertisers are.

And not just advertisers. Sports teams, civic clubs, schools and universities and even friends and spouses are understandably reluctant to be associated with anyone who has been RDW’d. You may know that your spouse is not a racist, but do you really want to be married to someone who is routinely called a racist? Or a sexist, or a homophobe, or a transphobe, or an Islamophobe, or anything else that is vaguely insulting but hard to disprove? Such stresses are the stuff of broken relationships.

The stigma of the reverse dog whistle is especially hard to shake off when the underlying accusation is only implied, not expressly stated. Call me a racist, and I can sue you for defamation. Accuse me of ‘pandering to racists’ or ‘enabling racism’ and there’s little I can do to clear my name. Whatever the merits of the RDW, most people understandably shy away from associating with commentators who are accused of pandering to racists. I may not be a racist, but the RDW suggests that if you associate with me, you may be one yourself.

In 2015, Spectator contributor James Bartholomew coined the term ‘virtue-signaling’ to represent a way of ‘indicating that you are kind, decent and virtuous’ without your actually having to do anything virtuous to earn the label. The reverse dog whistle is the dark arts counterpart to virtue-signaling. Instead of an easy way to say how good you are, it’s an easy way to say how bad someone else is. Instead of saying ‘come play with me because I’m nice’, it says ‘don’t play with them because they’re bad’.

Unlike virtue-signaling, which mainly just annoys people, the RDW actually works. So how can we stop it? It’s not clear that we can. Steve Bannon wants to demystify the charge of racism by encouraging people to stand up Spartacus-style and say ‘if he’s a racist, then I’m a racist too’. That’s just not going to happen.

Actual dog whistles have faded away as media outlets have sharpened their hearing and ordinary people have become less and less tolerant of intolerance. These days you only hear them in in the distant corners of the dark web. But reverse dog whistles dominate the public airwaves, and they are getting louder. Buy a good pair of earplugs, because they’re not going to tone down anytime soon.