Boris Johnson had many motives to dodge a televised debate with Jeremy Hunt on Tuesday night but one factor trumped the rest: he didn’t do it because he didn’t have to. If Conservative party rules and our bizarre constitution can combine to let a man like Johnson sidle up to Downing Street, answering as few questions as possible, it makes sense for him to try.

It is also natural that others should try to flush the frontrunner into the open. Hunt accused his rival of cowardice and the jibe clearly stung, as the truth often does. Johnson took to the airwaves, blustering ineffective rebuttals to the charge that he had anything to hide.

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These dynamics would matter more if the race involved a ballot of the nation and not a straw poll of Tory members, whose preferences are mostly set. “Boris in No 10” is the blockbuster they have been queueing to see after a long, hard marketing push. A few bad reviews might provoke a flutter of anxiety on the eve of release, but won’t make a big difference at the box office. The other candidates’ pitches are just trailers before the real show begins.

There isn’t much Hunt can do about that. He could be more aggressive on Johnson’s record of personal betrayals and professional derelictions. He could point to the slurry of lies and bullying behind the factory where Johnson’s chummy authenticity is manufactured. But to what effect? The most revealing intervention in the leadership hustings in Birmingham over the weekend was the growl of dissent that rose out of the audience when Johnson was pressed to clarify the circumstances of an argument with his partner. The reaction was reminiscent of the way Jeremy Corbyn’s activist audiences reprimand the media for disrespecting their icon. But there is a difference. Corbyn’s crowd believes he is beyond reproach and being maligned by wicked journalists. Johnson’s fans know he is flawed but don’t care, or don’t want to be reminded that they should care. Tugging at the mask spoils the fun.

Hunt cannot ingratiate himself with a Tory audience and attack his rival at the same time. (And he’ll want a plum cabinet job from the winner as consolation for being a sporting runner-up.) His hustings performances are wholesome and bland. He looks like an earnest parent at a children’s party handing out carrot sticks when all eyes are on the chocolate cake.

On Brexit, the two rivals’ positions are not miles apart. Both claim they will procure better deals than the one negotiated by Theresa May. Both struggle to explain how that can be done when the EU says the existing withdrawal agreement is immutable. Both claim they would be prepared to proceed through without a deal; only Hunt is explicit about the cost. He would do it, he says, “with a heavy heart”. But much of his audience sees that foreboding as the very reason why Brexit has stalled. They diagnose heaviness of heart as a morbid affliction of the May years and seek Johnsonian levity as the antidote.

Hunt doesn’t have a true bluffer’s panache but he also lacks conviction for a sustained, fact-based assault on Brexit fantasies. He is not a fearless truth-teller but a truth-impersonator, mumbling cover versions of what should be good arguments about tariffs and trade. That style is consistent with a career spent trimming sails to changing Westminster winds. Hunt has been in the cabinet since 2010. He survived May’s purge of David Cameron loyalists in 2016. He was a remainer who preferred a soft Brexit immediately after the referendum, when soft Brexits were still tolerated in the Tory mainstream, and then hardened his position to match his party’s ossifying anti-Brussels dogma.

That elasticity of belief – combined with Johnson’s tendency to spontaneous political combustion – are reasons not to write Hunt off completely. But the qualities he brings to the race belong in a different contest, from a different time. If the ability to hold down a cabinet job were considered vital, Johnson wouldn’t have made the starting line-up. One former Downing Street adviser told me that May only put Johnson in the Foreign Office to accelerate exposure of his feckless incompetence, and thereby hasten his disqualification from any higher office. Only the first half of that plan seems to have worked.

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Johnson’s slapdash dilettantism can’t be defeated by Hunt’s ministerial CV. If anything, a record of departmental diligence and attention to detail is offputting because it has a whiff of bureaucracy and Whitehall risk-aversion. It is the halitosis of remain to Brexiteer noses. Hunt’s message is all about seriousness. “I’m not going to say it’s going to be easy,” he tells his audience. But if the Tories were minded to contemplate the complexity of Brexit – and the strategic, legal and economic implications of rupture from the EU – they would have accepted May’s deal or abandoned the project by now. They are too deep in denial to ponder the downside. If they tug on all the threads of difficulty, they end up unravelling the whole tapestry woven from years of Eurosceptic mythology, and exposing the naked monstrosity of what they have undertaken.

Hunt doesn’t really want to pull at those threads, but nor can he ignore them. His campaign is a nervous fidget around the truth, supported by a beleaguered minority, nostalgic for a Conservative style that was fashionable before 2016. He is the candidate of a bygone era when most Tory MPs thought Johnson was a sinister clown who should never be allowed near Downing Street.

Now even many pro-European Conservatives are resigned to Johnson’s victory as the logical culmination of an ethos that treats any rational calibration of Brexit risks as a sign of moral debilitation. For Hunt there is no scrubbing off the stain of remain. Instead Tory Brexiteers need to see intractable problems confronted by the man who told them it would all be easy. And they will only believe there is a cliff edge when they see their cheerleader blanch at the drop – or later still, on the way down.

• Rafael Behr is a Guardian columnist