We thought Trump was the comic relief. Who’s laughing now?

What is your capacity for the cold, hard truth? If you went to the doctor with a scary symptom, would you prefer to hear: a) “I’m not going to lie to you, it may be something nasty”, so that if the test results came back positive a week later, you’d be cushioned against the shock? Or b) “I’m quite sure it’s absolutely nothing, but we might as well check it out to be safe”), giving you another seven days of relative peace?

If your choice is b), I must instruct you to leave this column immediately and find something less distressing to read. But if a) is your bag... Look, I’m not going to lie to you. A week from now there’s every chance that we will be talking about Donald Trump as a plausible presidential contender.

To the seemingly rhetorical question: “When does a delicious frisson of dystopian fear become a blast of blood-freezing terror?” the literal answer may be: “On 31 January 2016, mate.”

If Trump wins the Iowa caucuses next Monday, as the betting markets deem twice as likely as not, the conventional wisdom dismissing the prospect of President Trump as too absurd to contemplate will be redundant. He will not only be odds-on for the Republican nomination. He will be a short-priced second favourite for the Oval Office. Or rather, an even shorter priced second favourite.

All the excitement of his wrecking ball campaign against decency and the hilarity of Sarah Palin’s stream of semi-consciousness endorsement has disguised the hard truth that Trump is now an 100/30 shot for president. That equates to almost one chance in four – slightly less likely than Arsenal winning the Premier League, if context is required, but a little likelier than Andy Murray winning the Australian Open. Until now, more of that conventional wisdom further insisted that, even if Trump beats the repulsive Ted Cruz and those like Marco Rubio who pass in the modern Republican party for moderates, his colossal unfavourability ratings among Democrats and independents would make him easy general election meat for Hillary Clinton.

The one tiny drawback to the conventional wisdom in our febrile post-economic crash times is that, since it’s modelled on precedent from the more centrist pre-crash era, it increasingly resembles the conventional idiocy.

As with Jeremy Corbyn and the Labour leadership, everyone regarded as Trump as nothing more than the comic relief candidate – until he wasn’t.

It is too early to understand exactly how the Trump nightmare edged towards reality, but among the obvious factors are the raw power of a personality cult and his gift for tapping into the grievances of low-reading-age white voters. For almost half a century, America’s non-professional middle class has seen lives of comparative ease become harder as pay stagnated under pressure from an enlarged immigrant work force and outsourced manufacturing. Like the Afrikaner farmers of South Africa when apartheid ended, a sense of entitlement denied fuels vicious resentment. What they most resent, judging by the comments on race-baiting online “news” resources such as breitbart.com, is being made to feel guilty for racist thoughts they know they can no longer express, but without really understanding why. (“If it’s ok for rappers to use the “n” word, why not us?”).

So when a liberal, Ivy League insider who inherited tens of millions from daddy presents himself as an up-by-the-bootstraps crypto-fascist anti-establishment miracle man with quick fixes for troubles decades in the making, they couldn’t be less interested that the beliefs he espoused five minutes ago are anathema. They could not care less that recently Trump was pro-abortion and anti-guns. Even the women among the right wingin’, bitter clingin’, proud clingers of guns’n’god, to borrow from Sarah Palin’s exquisitely polished speech, couldn’t give a toss that Trump finds their bodily functions “disgusting”, or playfully cracks jokes about fancying his own daughter (an obvious vote-winner, when you think about it, in the Appalachians). When he depicts the US military as cripplingly underfunded, they leave the reality in which America still spends more on defence than the next nine biggest spending powers combined and find sanctuary in the alternate universe in which this putrid, mad-coiffed demagogue is a visiting messiah who speaks the truth of god.

Two commodities he gives them are potent enough to relegate all other criteria to irrelevance. He legitimises their Jim Crow racism by affecting to share it, and offers hope that he can pop the US in a gold-plated Tardis and return it to 1956.

We know here that the appeal of fantasy-regressionist politics extends beyond the reactionary right. In May’s general election, Ukip damaged Labour more than the Tories. If disaffected working-class people in industrial northern England flocked to Ukip, why won’t they flock to Trump in the industrial swing states of Ohio and Pennsylvania? And if early wins in Iowa and New Hampshire give him the momentum to wrap up the nomination quickly, why wouldn’t this deceptively canny operator spend six months backtracking from the doolally and softening his tone to target disaffected independents and Democrats?

Traditional Republican candidates driven to extremes to win the nomination (see Mitt Romney) are too hamstrung by their previous positions to make it back to the centre ground. Trump can reverse anything without damaging himself because the one thing no one seeks from a messiah is consistency. Odds are no more than rough guides and the odds remain firmly against him reaching the White House. But a buoyant Trump with more free publicity than he can use and unlimited spending power versus a stale, fatigued Hillary looks nothing like a rank outsider.

So brace yourselves for some bad news. If the contemptuous laughter hasn’t taken on a nervous timbre yet, it probably will next week.