We have so much to worry about, it’s a relief that at least one big source of angst is no longer there to keep us up at night. Given how much psychic energy so many – inside the US and out – once devoted to him, how he came to invade even our dreams, there is solace in the fact that these days we need pay no more attention to Donald Trump. Right? I’m afraid not.

True, the great orange spectre has disappeared from the social media timelines, exiled by the emperors of Facebook and Twitter, reduced to starting his own blog to get around the ban – an effort that, like so many Trump enterprises before it, was quietly abandoned in failure. It lasted a month.

So each morning no longer begins with a peek through splayed fingers at the phone to see what fresh horror Trump has committed. But just because he is out of daily sight does not mean he should be out of mind. Tragically, to the world’s most powerful democracy and all those who, for better or worse, are tugged like the tides by its lunar pull, Trump still matters. He cannot yet be consigned to the past, because he is affecting the present and looms over the future.

The clearest evidence is the expectation that he will win the Republican presidential nomination for a third time and be the party’s next choice for the White House. You need only take a look at admittedly premature polls of the putative Republican field for the next election: he’s at the top, every time, with 76% of Republicans viewing him favourably. It was scarcely a shock when the Trump-backed candidate beat better-qualified rivals to win a Republican congressional primary in Ohio this week. Not for nothing does the former Bush speechwriter David Frum say of Trump, “Unless he’s dead or otherwise unable by then, he’s the likeliest 2024 nominee.”

At the risk of haunting your dreams all over again, that is a daunting prospect. For election day 2024 will be just a few days shy of Joe Biden’s 82nd birthday. If the president runs, he would be asking to remain in the Oval Office until he is 86. Many Americans would hesitate before granting that request. (At a mere 78, Trump will be able to run as the youth candidate.) But if it’s not Biden, if it’s Kamala Harris – or, frankly, almost any other Democrat – Trump will be able to hum the familiar culture-war tunes that brought him victory in 2016 and took him perilously close in 2020.

But let’s say that scenario is both too distant and too gloomy. Let’s say that, for whatever reason, it pans out differently. Even then, there is little scope to relax. Because even if Trump never returns, Trumpism is already in the American bloodstream.

Some hoped that the 6 January attempted insurrection might finally break the spell, disenchanting those Republicans who had remained loyal to Trump in the belief that, even if he was gross, crude and bigoted, extravagantly selfish and self-regarding, he was ultimately harmless. The optimists reckoned that the sight of the head of the US government rousing a mob to storm the US Capitol – a mob bent on using force to overturn the results of a democratic election – would finally persuade most Republicans that on this critical point their political opponents were right: Trump did, after all, pose a grave threat to the republic.

But it has not worked out that way. Republicans in the House voted against impeaching Trump for his crime, while Republicans in the Senate voted to acquit him of it. Dissenters have been ostracised. Even her pedigree as the daughter of a conservative hardliner has not protected Liz Cheney, expelled from the House leadership for standing against the great leader. Riding high instead are the conspiracy theorist Marjorie Taylor Greene and her comrade Matt Gaetz, the latter reportedly under investigation for sex trafficking, because they pass the only litmus test that matters: loyalty to Trump.

The baseless claim that the 2020 election was stolen, that Donald Trump remains the true president and that Biden is a usurper, was once merely the stuff of Trump’s fever dreams, a psychological mechanism to protect his ego from the truth of defeat. But “Stop the Steal” is now an article of Republican faith. Nine months on, a majority of Republicans believe Trump won and Biden lost, against all the evidence and a string of court judgments finding every claim of voter fraud to be groundless.

It seems nothing will shift the conviction of the faithful, not even the latest confirmation that it was Trump, not Biden, who was determined to rob the people of their democratic will: “Just say that the election was corrupt [and] leave the rest to me,” Trump told his acting attorney general last December, according to a newly released note taken by the latter’s deputy. Meanwhile, an Arizona state senator has called for election officials to be held in solitary confinement.

The Republican tribe cleave loyally to the other defining feature of 2020 Trumpism: the refusal to believe in the reality of Covid and to do what’s needed to thwart the virus. And so the single greatest predictor of whether an American has been vaccinated or not is whether they voted for Biden or Trump last November. As of last month, 86% of Democrats had received at least one shot; among Republicans it was only 45%.

That’s no surprise when Republican politicians compare the vaccination drive to the Nazi persecution of the Jews or to the KGB knock on the door and when Republicans at state level have forced out public health officials for pushing the vaccine too energetically.

Of course, these twin tenets of Trumpism are conjoined. What they share is disdain for expertise and contempt for facts, whether the experts be scientists or election officials and whether the facts relate to the nature of a virus or the sum total of votes cast last November. Trumpism demands instead that the facts bend the knee before the mighty helmsman. It is truth that must defer to the ruler, not the other way around.

Occasionally, you see a Republican who understands what’s happened to their party. There’s a snippet of video in which it pays to watch the face of the governor of Arkansas as an anti-vaxx heckler shouts down a briefing from a state medical official. In that moment, the governor seems to know that his party no longer believes in science or democracy, that the virus of Trumpism has infected its every organ. Whether or not Trump himself returns is almost secondary. The disease has already devoured the political party that constitutes half of America’s body politic – and it’s not done yet.

• Jonathan Freedland is a Guardian columnist