The far right is defining politics. To understand how, imagine a line dance where each dancer takes a step to the right and points an accusing finger at the person next to him.

You think we’re selling out British workers, says Labour, by not fighting for Remain, and threatening jobs and living standards by taking us out of the single market? Don’t think about what we are doing (steps to the right and points) – look at Theresa May’s deal that wouldn’t even keep us in customs union.

We’re not having that, say Rory Stewart and the remaining supporters of Theresa May in the Conservative party. Our critics accuse of us abandoning the service sector and caring nothing for 80% of the economy. But you shouldn’t dwell on our faults. At least we are being honest when we say there is “no evidence” that the EU will renegotiate the withdrawal agreement – none whatsoever. We’re not the bad guys. Look (step to the right and points), just look at Jeremy Hunt and the other supposedly pragmatic Tory leadership candidates.

Sajid Javid is pretending there’s a sci-fi solution to the Irish border that exists only in his head. Jeremy Hunt says the deadlock could be broken if he takes the Tory party’s most extreme Brexit supporters to Brussels. Michael Gove says he has the magic power to renegotiate a withdrawal agreement that the EU has said explicitly and repeatedly it will not reopen. To describe their plans as fanciful is to insult the fairies at the bottom of the garden.

But Javid, Hunt and Gove have their defence ready. How can you accuse us of lying to the Tory party, country, maybe even ourselves? We are as nothing (step to the right and point) when compared to the greatest charlatan in the history of the Conservative party: that incompetent, manipulative, lazy, overentitled, media-constructed and media-protected fatberg of dishonesty, Boris Johnson.

They have a case. Johnson repeats the faults of his rivals and adds some new ones just for fun. The sci-fi Irish border, that is there but not there, and the reopening of closed negotiations are in his prospectus, but then comes the clincher. “Boris”, as the sycophants who have taken over the once rough trade of journalism call him, believes he can save the country by imitating Donald Trump and going in “bloody hard”. Don’t panic, says the Tory party’s Corporal Jones. Foreign Johnnies don’t like it up ’em. If you create “all sorts of breakdowns, all sorts of chaos” in Europe, “actually you might get somewhere”. Actually, you get nowhere because European politicians detest Johnson with a justifiable passion and would do nothing to help his premiership.

Surely Tory MPs would never be so unpatriotic as to inflict this character on a nation in no fit state to take him. Ruth Davidson, Damian Collins and many another Tory “moderate” intends to do just that. When we scream: “How could you?”, they say (step to the right and point) it is not Johnson we should worry about but Dominic Raab. For, as a stunned nation has learned, behind the anxious face of an unprepossessing middle manager lies a home counties Mussolini. To get his Brexit deal, which, naturally, is no deal, Raab would mount a coup d’etat and order the Queen to suspend parliament. Once power was his, he would cut taxes on what wealth we still possessed so deeply it’s hard to see how our underfunded public services could function.

Surely with Raab we’ve reached the end of the line? Surely the only thing further to his right is the stage wall? Not so. For although he would rule without parliament, Raab has his scruples. As he explained last month (turns to the right and points): “If I am elected I would not do an electoral pact with Nigel Farage.” Is Farage where it all ends, then? No, Farage declares. He is a respectable politician when set against the Islamophobes of Ukip, who are likely to “inspire violence and thuggish behaviour”.

Dominic Raab ‘would mount a coup d’etat and order the Queen to suspend parliament’. Photograph: Mark Thomas/REX/Shutterstock

Everyone covers everyone else. Everyone indignantly rejects the accusation that they are following extremist policies by pointing to the right and saying: “If you think I’m the far right, you should see the next guy.” “Mainstream” politicians are not defined by their opposition to the far right but by their willingness to adopt extreme anti-European policies that are not quite as extreme as their nearest rival.

Not one of the factions contending for the leadership of the our country is saying that Brexit will bring tangible benefits. All they can say is that the alternatives to their terrible plans are worse.

With the partial exception of Stewart, no one is telling the truth. Supporters of a no-deal Brexit talk as if they have a brutal but honest programme. They neglect to mention the cost or to say that, if we crash out – either by design or because the EU gives up on us – the EU will insist, when and if we return for a trade treaty, that Britain accepts the terms of the withdrawal agreement.

As the dancers crowd into each other’s space, most of the stage is empty. The contest to become the next prime minister is shocking and not only because the electorate is limited to 313 Conservative MPs and 120,000 or so Conservative members. Not one candidate represents the half of Britain that wants to stay in the EU. Not one represents the moderate Leavers and Remainers who would accept a Brexit that kept us in the single market. The debate is pinched and policed on all sides. The limits of the possible have been shrunk too far for an open society to tolerate.

The participants should have fair warning: their dishonesty today means hardly anyone will be happy with whatever botched or brutal Brexit emerges. Everyone from Stewart to Farage says they are against a second referendum. If I were them, I would be desperate to get democratic consent rather than bear sole responsibility for the stinking reviews their turkey of a show so richly deserves.

• Nick Cohen is an Observer columnist