The 2020 US presidential election is going to be about native entitlement. It’s going to be about race and immigration and deportation and Israel and every other wedge issue Donald Trump can summon to split the vote into “us” and “them”. He will become Chief Native, swelling his supporters’ sense of dominion over others less white. The campaign has already started; his social media presence has gone from ungainly swiping to a more coherent regular punching. He has in effect launched a cyber-bullying offensive.

Trump will reduce people to tears, from black TV anchors worn down by his racist attacks to Rashida Tlaib, reeling from the unexpected emotional shock of her Palestinian grandmother being dragged in the mud of Trump’s bear pit. He will tell Jews how to vote and nurture antisemitism while pretending to give a damn about Israel so that he can smear Muslim opponents. What was a prominent theme in the 2016 campaign, going after Muslims and immigrants, will become the only theme.

It might appear to be an unprecedented escalation, but Trump is only the latest Republican politician to leverage white identity politics for electoral gain, the only difference, as with everything else that sets him apart from his predecessors, is that he is not intelligent enough to do it subtly.

There really are no more excuses. A Trump voter in 2020 is a voter who can no longer plausibly pretend, to themselves or others, that their reasons are down to economic anxiety or some “left behind” resentment. Yet these excuses will be rolled out anyway, so established are the patterns that let voters off the hook for supporting racial supremacy. In 1990, a former Ku Klux Klan grand wizard, David Duke, ran for Senate in Louisiana and secured 43% of the vote. One could not distinguish between the justifications for voting for Duke then and the reasons white people voted for Trump in 2016: a working-class post-recession revolt; an angry message from the disenfranchised to the elites of Washington.

Facebook Twitter Pinterest ‘The Squad’: (left to right) US representatives Ayanna Pressley, Ilhan Omar, Rashida Tlaib, Alexandria Ocasio-Cortez Photograph: Erin Scott/Reuters

Duke only lost because black people voted overwhelmingly against him. The same happened almost 30 years later when Roy Moore, Alabama’s Republican candidate for the US Senate, ran what the Washington Post called a “white populist” campaign. Moore romanticised the era of slavery, referred to Native Americans and Asian Americans as “reds and yellows”, questioned whether former president Barack Obama had been born in the US and argued that Muslims should not be allowed to serve in Congress. He was thwarted, because black people voted against him.

Despite this history, the Democrats are still not ready. They are still unable to fully engage in the looming identity wars of 2020. Trump’s entire political strategy has become reduced to identity politics not only because he is incapable of anything more sophisticated, but also because it gets results. The leftwing establishment (for so long accused of playing the identity politics card) is taking the blows passively, having internalised the largely baseless accusations that it is out in the wilderness because its message was too focused on minorities.

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This might have been true at some point, when there were big electoral gains to be made after the 1960s when discreet marginalised groups became identifiable as voting blocks and the left wooed them. But lately the left’s overtures towards those groups have been mainly to make the right noises and take them for granted. The result was that in 2016, the black voter turnout rate dropped for the first time in 20 years in a presidential election. The 7% fall was the largest ever recorded for that demographic.

There is no success in political battle more unequivocal than convincing your opponent that they are wrong. The right has managed to succeed not only in persuading voters that the left is obsessed and distracted by identity politics at their expense, but in planting this seed of self-doubt in the minds of leftwing politicians themselves. Steve Bannon summed this up. He couldn’t “get enough” of the left’s “race-identity politics” he said. “The longer they talk about identity politics, I got ’em … I want them to talk about race and identity … every day.” Only Trump is allowed to talk about race and identity every day. The only acceptable way to wield racial politics these days is against its victims, rather than in their defence.

The hesitation is everywhere, from the Democratic party leadership’s reluctance to weigh in forcefully enough in defence of “the Squad” – four congresswomen of colour targeted by Trump, or “four people” who “didn’t have any following”, according to House speaker Nancy Pelosi – to the liberal media’s pearl-clutching at calling Trump racist (“We are not fucking part of the resistance,” according to a New York Times staffer). The mainstream American left is hamstrung by a misplaced sense of decorum and fixated on an outdated view that tackling the Trump assault head-on is somehow “radical”, a strategy that will dent the Democrats’ ability to win due to a loss of “moderates”. All this despite the fact that the whole “when they go low we go high” approach didn’t work out so well in 2016.

And it won’t work this time either. The left must dive into the identity politics pool, convert the jaded and make a pitch for the soul of those Trump’s vision has captured by showing how his incendiary politics makes the world less safe for everyone. Not only because it is the right thing to do, but because it works. And because there really isn’t much of a choice any more. A recent poll showed that independents in Wisconsin (a crucial swing state won by Trump three years ago) cite “immigration” as their top electoral issue.

For those crucial defecting Democratic voters (about a third of Obama-voting counties flipped for Trump in 2016), there are already signs that the “change” candidate they saw in Trump has not delivered. This cohort will be even more susceptible to being won back by a Democratic party pitching in a positive, explicitly inclusive way, rather than fixating on Trump’s failures. Inspiring emotion is often more effective than delivering information. When the New York Times canvassed voters in Ohio, the big takeaway was: “Several voters said they chose Mr Trump for the same reason they chose Mr Obama: a deep craving for change.”

The evidence this approach works is Trump himself, a man who has nothing to offer but a coherent vision of the future. In a recent interview Alexandra Ocasio-Cortez said: “Whether you like it or whether you hate it, a wall is a vision, it’s a tangible vision that is symbolic and representative and galvanising. And if we do not have an ambitious, inspiring, galvanising vision, I think we risk losing even more.”

To prepare for 2020 the Democrats must hold their noses and wade into the immigration and race melee. They must do it with conviction, consistency and emotional resonance, rather than with a sort of competent, managerial presence that frowns upon engaging with Trump on his own terms as unruly. Being reactive and “fact-checking” Trump can only get us so far. The fight must be both dirty and inspiring. It needs to get to a point where a Democratic presidential candidate can say: “The longer Trump and the Republicans talk about identity politics, I got ’em.”

• Nesrine Malik is a Guardian columnist