A man — later described with those inevitable words “loner” and “kept to himself” — kills a pro-EU British Labour MP, allegedly yelling “Britain first” as he stabs and shoots her repeatedly. The focus is immediately on his mental health — after all, he has a well-recorded history of mental health problems.

If he’d shouted “Allahu Akbar” or claimed allegiance to Islamic State, however, we’d be seeing very different coverage of the murder of Jo Cox — of the latest IS atrocity, inevitably “striking at the very heart of rural England”. The media aren’t quite as ready to talk about terrorism when it’s a white man involved in acts of political violence. For many in the media, white men, despite being the primary perpetrators of violence in Western countries, despite being identified as the current greatest terrorist threat in the United States, despite the long history of left-wing and nationalist political violence up until the 1980s in Europe, don’t do terrorism.

There is a definite politics of labelling at work in all this, because the way we name things is critical to how we frame events and the narratives that ensue. Like those forms of magic in which knowing the “real name” of an object or animal could bestow power over it, labelling is about control. Barack Obama this week criticised Republicans who complain that he doesn’t use the term “radical Islam” about terrorism. My colleague Helen Razer accurately noted the demand for labelling the Orlando massacre as a “hate crime” raises serious issues. The right in Australia perpetually complains that the left fails to talk enough about the failings of Islam and its connections to terrorism.

Our obsession with labelling has real-world consequences. In a radio discussion I had with Wendy Harmer this morning, a Muslim talk-back caller explained that he had heard about the murder of Jo Cox last night and, before further details of her murderer came to light, he was praying it wasn’t a Muslim perpetrator, because it would lead yet again to verbal and perhaps physical attacks on Muslims, including his own family. And obsessing over labelling can also lead all of us — no matter what political orientation — to ignore the most important thing, the lives lost to violence.

It’s not merely labelling that flows through into the real world. Other words do, too. The rhetoric of politics isn’t only rhetorical — tone matters in political debate; it can shape how people feel, it can legitimise or delegitimise, humanise or dehumanise participants. In the aftermath of Cox’s murder, this is being recognised even in a conservative outlet like The Spectator (the quality UK publication, not the dreadful Australian knock-off).

Nearly all of us involved in public debate are guilty of this — every time we play the person and not the ball, every time we impute sinister motives to those we criticise, every time we strain for rhetorical effect, reach for ever more “cut-through” in an increasingly unviable media industry, to get those clicks, to go viral.

The broad left can be guilty, too: “calling out” racism in opponents is often entirely legitimate, identifying the racism that underpins the position of powerful institutions can serve to illuminate and inform. But it also often uses the claim of racism, or some other expression of identity politics, simply as a means of shutting down debate and delegitimising opponents, regardless of any actual bigotry on their part.

But when deployed by rather than against the powerful, the rhetoric of delegitimisation becomes more dangerous than a mere threat to free speech and meaningful debate. The violent, bigoted rhetoric of Donald Trump is echoed and amplified in the anger and aggression of his supporters and his rallies, where death threats and threats of violence against pretty much everyone outside the Trumposphere are common. What Trump has tapped into is the inchoate rage of white Americans, particularly white American men, who feel dispossessed and disoriented by a third of century of neoliberal economics, Republican promises to fix things that never deliver, and social change that has empowered other communities — women, African-Americans, Latinos and LGBTQ people — and thus is seen as disempowering of “traditional” white males. They’ve lost their jobs, they’ve lost their incomes, they’ve lost their social status, and they’re ready to back someone who promises to magically restore those.

Trump’s self-anointed status as an outsider — his opponent, Hillary Clinton, was an honoured guest at Trump’s third wedding in 2005 — is crucial to tapping into that anger, because it must be directed at an unaccountable elite that is responsible for those social and economic changes. That’s not to suggest there aren’t powerful elites who strongly influence public policy — large corporations, the politicians they fund, the media that acts as their cheerleaders. But the concept of “unaccountable elites” is a staple of right-wing rhetoric, an implicit assertion that there’s a conspiracy of powerful interests at work against “ordinary people” (read: white heterosexual Christian people). But note that Trump is no traditional right winger: his position on trade and industry policy wouldn’t be out of place on the hard left — he is vehemently opposed to free trade deals and wants to compel large American companies to “onshore” jobs. His stance on immigration is also a traditional left one, albeit at odds with the cultural left.

And above all, the anger that should be directed at the corporate, governing and media elite in the US has been redirected by Trump downward at the marginalised — immigrants, Muslims, women (he directs it at the media, yes — but only those that subject him to scrutiny. In fact, as a reality TV show star, Trump himself is part of the media elite).

Trump’s message is similar to the appeal of regional independents in Australia in recent years, like Pauline Hanson, who also directed white rage downward at immigrants. Trump’s economic message is now echoed here by a very different politician to Hanson, Nick Xenophon, who offers a strong reaction against neoliberalism in favouring of overt interventionism, conveying a sense to the disempowered and the economically marginalised that the protective, protectionist world of the 1960s that many of them grew up in can be restored.

Similar themes run through the Brexit campaign, where older, and more poorly educated, voters and those engaged in manual labour occupations are the ones more likely to want to leave the EU. That campaign has successfully exploited concerns about immigration — and that fact that the Cameron government promised to dramatically reduce the level of immigration to the UK and has been unable to do so because of immigration from EU countries. The campaign has also associated the “Remain” camp with British elites — ludicrously, given a key Brexit leader, Boris Johnson, went to Eton and Oxford like his (erstwhile) good friend David Cameron. In fact Brexiteer Tories and other Leave campaigners have combined elites and immigration into a single narrative in which a “metropolitan political elite” has “betrayed” and “abandoned” ordinary Britons as immigrants flood the country. Arch-Brexiteer Nigel Farage has even suggested violence is “the next step” if ordinary Britons feel the country has lost control of its borders and don’t get their way by voting.

Like Trump’s fake status as an outsider Boris Johnson’s pose as a foe of an out-of-touch elite serves to disguise that their rhetoric of delegitimisation isn’t aimed upward at the powerful but ultimately downward at the marginalised who have, somehow, been able to displace white middle-aged lower income people from their privileged status in US and UK society.

That some people — whether because they have mental health problems or simply because they have been stoked to uncontrollable anger — decide that violence is indeed the “next step” to deal with what they’ve been constantly told is an elite conspiracy against them reflects yet again that labelling, and language, are critical. If it’s accepted that the message of IS — for adherents to attack non-believers wherever they may be — delivered via social media has the capacity to influence some individuals, then how much more so a message that is given mainstream media coverage and wears the friendly face of high-profile political figures?

Delegitimising rhetoric in Australia is hardly absent from our political discourse. Even ignoring Pauline Hanson, who may very well secure a Senate spot on July 2, Immigration Minister Peter Dutton has overtly demonised refugees; some Coalition MPs peddle profoundly Islamophobic and homophobic claims unchallenged by their party leaders. Islamophobic and anti-racist protesters clash violently on the streets of Melbourne. It’s irresponsible to suggest we’re likely to see similar events here to the ones recently seen overseas. But it’s hard not to see the murder of Jo Cox and think, there but for the grace of god …