Pundits and polls are at one in predicting a victory for Joe Biden over Donald Trump in the presidential election, portraying the vote as a non-military rerun of the Battle of Gettysburg in 1863, when the north defeated the south in what is regarded as a turning point in the civil war. The violence will be less this time round, but the hatred between the antagonists is at a similar level.

A comparison with the civil war is appropriate because the confrontation between Trump and Biden echoes the armed conflict a century and a half earlier. White America had broken up into two nations then and, to a significant degree, it is two nations now. Trump’s core support is in the south and rural areas; Biden’s is in the north and metropolitan cities.

The match between the two periods is not perfect and the geographical boundaries that define the two different American national identities have changed. Yet, at the core of Trumpism is the white male evangelical Protestant brand of American nationalism that originates in the south and, since the Civil Rights Act of 1965, has blended with and largely taken over the Republican Party. It has transmuted into a radical American nationalist party, its ideology a toxic combination of racism, chauvinism, messianism, social conservatism and free market economics. It enhanced its political punching power by becoming the vehicle for the grievances of the white working and middle class, whose social and economic security has crumbled under the impact of globalisation and new technology.

It was a strange alliance of billionaires and the left-behind that propelled Trump into the White House in 2016, and it would be good to believe that it will face its Gettysburg moment on Tuesday. Battered by almost four years of Trump’s megalomaniac rule, a majority of Americans from Black Lives Matter supporters to long-standing members of the establishment cannot wait for this to happen. Conservative columnist George Will wrote confidently this week that we were seeing the moment when “the Donald Trump parenthesis in American history closes”, while the Republican Party that enabled his rise was facing a political massacre.

Great if this is true, but Trump has often succeeded against the odds, as he did against Hillary Clinton, because his opponents underestimate him. Crude and mendacious he may be, but he is an extraordinarily effective campaigner, much aided by the ineptitude of the Democratic Party leaders.

Fortunately, the breaks that went in his favour in 2016 are now going against him: the coronavirus itself, the consequent economic collapse, his own infection, and the virus sweeping through states that he needs to win in the last days of the campaign. Panicky headlines on the front pages of newspapers in Wisconsin are all about the surging epidemic there, making Trump’s efforts to play down the illness sound crazed and self-destructive.

A pundit like George Will, along with most of the media, wants to see Trump as a “parenthesis”, an appalling aberration in American history, but here they are on shaky ground. The election of Trump may have been one of history’s wild cards, but he is only facing defeat because of an even wilder card in the shape of the onset of an unprecedented pandemic. Late last year, he had a good chance of winning a second term on the back of a booming economy, given that few sitting presidents had been displaced when the economic winds blew in their favour.

No wonder Trump appears to rage against the virus itself, ludicrously belittling its virulence and deadliness, even though it has so far killed 225,000 Americans.

Yet the very fact that it has taken the coronavirus to defeat Trump is evidence, unfortunately, that he is not the aberration or parenthesis that his opponents think him to be. Conviction that he is stems from wishful thinking by many Americans – and a majority of commentators – who detest him as a satanic figure whose rise to power is a horrible historic joke. But such an interpretation, understandable though it may be, underestimates the strength of the forces that backed him and seriously misreads American history.

All countries where slavery was an important institution find it almost impossible to escape a legacy of racial fear and hatred that does not dissipate long after its formal abolition. This is as true of Caribbean islands, where slaves worked in the sugar plantations, as it is of the former slave states in America. Gettysburg was the political and military turning point of the civil war – or is so remembered because of Lincoln’s Gettysburg Address – but the defeat of the Confederacy in 1865 did not mean that America ceased to have three different national identities roughly centred on the north, the south and the black community. Clashes and combinations between the three are what makes American culture different and interesting.

Trump fanned and exploited these racial and cultural divisions, but he did not invent them. The north’s military victory destroyed slavery, but it was replaced by the systematic apartheid imposed on black people by the Jim Crow laws. Discrimination was supposedly ended by the civil rights legislation of the 1960s, but the real benefits for black Americans were meagre and uneven, and the counterattack against racial equality had much success against such progress as was made.

At the beginning of the 21st century, it was calculated from official figures that one in three black men would go to prison during their lifetime. As Michelle Alexander wrote in The New Jim Crow: Mass Incarceration in the Age of Colourblindness: “Rather than rely on race, we use our criminal justice system to label people of colour ‘criminals’” – and then engage in all the discrimination that had supposedly been outlawed.

Ensuring that black people have “felon” status and therefore cannot vote has been central to Republicans winning elections in states like Georgia, Florida and Texas – and may do so again on Tuesday. An important ingredient in Republican success in voter suppression has been the Democratic Party’s failure to combat it effectively. Indeed, Biden’s energetic role in passing legislation that criminalised a significant part of the black population is constantly highlighted by his critics. His supporters prefer to focus attention on the Supreme Court decision in 2013 that struck down a key provision of the Civil Rights Act and allowed Republican-dominated states to gerrymander districts, cut the number of polling booths, and otherwise limit non-white minorities ability to cast their vote.

Voter suppression on a mass scale may not be enough to see Trump re-elected, but its impact should not be underestimated: it was probably decisive in his winning the narrowest of victories in 2016 (much more important than anything the Russians could get up to). A landslide Democratic victory might give them the strength, though perhaps not the will, to reverse the cumulative disenfranchisement of minorities.

“America will never be destroyed from the outside,” Abraham Lincoln is quoted as saying. “If we falter and lose our freedom, it will be because we destroyed ourselves.” The prospect of such destruction came very close during Trump’s years in the White House and has not yet disappeared. If he stays there, of course, it will be a Gettysburg in reverse, fulfilling Lincoln’s dire forecast.

Patrick Cockburn is the author of War in the Age of Trump (Verso).