In the wake of the tragedy of Pittsburgh, the murder of 11 Jewish people at a synagogue in America’s most deadly act of antisemitism, we have heard a repeated cautionary refrain: that words have consequences. Donald Trump’s White House denies that the president’s rhetoric has any impact on reality. But others have noted that the “apparent spark” for the Pittsburgh murders was a “racist hoax” inflamed by the US president, who in the run-up to the US midterm elections has been scaremongering over a Honduran caravan of refugees fleeing violence and travelling to the US border to seek asylum, feeding antisemitic conspiracy theories that it has been funded by Jews.

That words have consequences is known viscerally to anyone whose identity is felt to be contested. Minorities, migrants and LGBT communities know all too well the terrible power of words to animate unconscious biases and rouse animosities; to poke at prejudices, stir hatreds and seed divisions. Words aren’t the only factor, but they create a context. Language is core to the architecture of antisemitism: words have, in recent memory, created the conditions for appalling violence and, ultimately, genocide.

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In those terrible Pittsburgh murders, we saw the heinous power of words compounded, as we learned that the killer’s hatred of Jews merged with hate for migrants. This is a confluence pushed by the far right, in one of many hateful conspiracies directed at the philanthropist George Soros and beyond: that Jews seek to destabilise western nations by flooding them with migrants, some of whom are Muslims. These are the layered weapons of the far right: vile demonisation directed at Muslims, migrants and Jews interchangeably, depending on which is more socially acceptable, and which results in the most political traction.

This is why an attack on one minority group is so keenly understood as an attack on all. But such understanding must also underpin the words we use. If progressives are to face down the far right, there has to be a reckoning with our own prejudices, which set us against each other and dilute our opposition to destructive nativism.

It’s this that partly explains the frustration felt by British Jews over the left and antisemitism. When the left that is standing in solidarity against racism also struggles to see the antisemitism within its own ranks, its voice rings painfully hollow. Now more than ever, with the far right a politically resurgent menace, we need the left to weed out its own bigotries. And yet right now, on social media, some of the response to Jewish people discussing the horrors of Pittsburgh is: what about Palestine? Even when Jews are killed for being Jews, they are, for some leftists, taking up too much attention, and deflecting from a greater cause for which they are collectively responsible.

Meanwhile, those supportive of Jewish people in this row over antisemitism may elsewhere talk of “cultural concerns” over immigration, or worry about the “pace of change” – feeding a nativist narrative of immigration as a perceived threat, as opposed to just a historical and necessary fact of life. Across the political spectrum, we have pandered to a hostile view of migrants, with terrible consequences for those at the receiving end of racial hatred and for our political culture, now infused with dangerous bigotry.

A frighteningly casual hostility to Muslims has also become mainstream – a prejudice that the former Conservative chairman Sayeeda Warsi pointed out some years ago had passed the dinner-table test. Small wonder, in this grim context, that the number of religious hate crimes in the UK has hit a record high, with half of those attacks directed at Muslims.

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Often the tendency is to rail against the prejudice we find most obvious while ignoring or downplaying others. You might insist that a particular bigotry exists only, or to a greater degree, on your political opponents’ side of the spectrum. Or you might view race hatred in a hierarchy, arguing that some minorities get more attention for their cause, or are less seriously attacked. Or perhaps you find it easier to see the operational mechanisms of one prejudice over another, or understand the coding of one group as a racialised minority more readily than another – which is how we end up with assertions that “Islam isn’t a race!” or that Jews are politically “white”.

We all have our blind spots. And they are the chinks in our defence, the weaknesses that far-right nativists are able to push through. Resilient communities construct inclusive narratives that are constantly on the lookout for such vulnerabilities. Kneejerk declarations that one particular side is prejudice-free are, in this context, a clear warning sign. If solidarity with one minority group under attack is to be effective, it has to be solidarity with all. And it has to go beyond mere words.

• Rachel Shabi is a writer and broadcaster