Pretty much the whole intellectual gap (if we can dignify it as such) between the candidates in the Tories' leadership contest is summed up in two tweets this morning that react to the Conservative humiliation in the Peterborough by-election.
One tweet was by the Foreign Secretary Jeremy Hunt, the other by his predecessor Boris Johnson. And I will come on to the dispute between them after weighing the catastrophe that Peterborough was for their party.
In what for years was a relatively safe Tory seat, the Conservatives slumped from second place to third, suffering a fall of 25 percentage points in their share of the vote, compared to the result in the 2017 general election.
If a swing of anything like that to the newly formed Brexit Party occurred in a general election – and the Brexit Party came second in Peterborough with 29 per cent of votes cast – the Tories would literally be wiped out. It would become a minor party, in the way that the Liberals did after the first world war.
Peterborough confirms that the collapse in Tory support manifested in the European and local elections is a real phenomenon. So how should the party respond?
Well the front-runner to succeed Theresa May as Tory leader and PM, Boris Johnson, says 'Conservatives must deliver Brexit by 31st October or we risk Brexit Party votes delivering Corbyn to No 10.'
And Jeremy Hunt – along with Gove, Johnson's nearest rival in a field as huge and open as that for the Grand National – says 'no future for our party until we deliver Brexit – any elections before then will just allow Corbyn to sneak through the middle.'
Now you would be forgiven for thinking Hunt and Johnson are making the same point. They are not.
Johnson is saying the UK must be out of the EU by the current due date of 31st October, or the Tory Party will be marginalised and supplanted by Farage's Brexit Party.
Incredibly disappointing that our brilliant candidate for Peterborough @paulbristow79 was not successful. No future for our party until we deliver Brexit - any elections before then will just allow Corbyn to sneak through the middle. But when the UK has Brexited, we will be back!
— Jeremy Hunt (@Jeremy_Hunt) June 7, 2019
Hunt is saying something subtly and crucially different, and which is the whole thrust of his case against Johnson.
Hunt believes that 31st October is an artificial deadline and that aiming for it means signing up to a no-deal Brexit (which, of course, Johnson is explicit that he does). Hunt credibly argues that Parliament would block said no-deal Brexit and – whether by design or accident – a general election would ensue, in which the Tories would be consigned by Farage to the dustbin of history.
So to put it another way, pretty much the only question that will matter when Tory MPs grill all those aspirant PMs in next week's hustings is whether – for them – 31st October is a hard or soft deadline.
For Johnson – and Leadsom, and Raab, and McVey – Brexit day of 31st October is not a moveable feast (or famine, depending on your leanings). For them we're out on 31st October or bust.
For Hunt, Gove, Hancock and Stewart, a managed, deal-based Brexit is the aim, with the timing of that Brexit still negotiable (up to a point).
Commiserations to the excellent @Paulbristow79 who did not deserve to come third in #Peterborough. Conservatives must deliver Brexit by 31st October or we risk Brexit Party votes delivering Corbyn to No10.
— Boris Johnson (@BorisJohnson) June 7, 2019
By the way, my assumption is that Harper and Javid are on the Hunt/Gove side of this argument. If I am wrong they know where to find me.
Now, as is characteristic of so many Brexit-related arguments, this dispute between Johnson and Hunt is not amenable to definitive settlement by pure reason – since there are too many uncertainties, around how EU leaders and officials would react to the choice of the next Tory leader, how MPs would behave, what the Speaker of the Commons will do, how markets and businesses will react, what happens to the mood and preferences of voters, and so on.
So Tory MPs will make their choice based on faith and fear: faith in one or other model of Brexit, and the capacity of any candidate to execute it; fear of a premature general election.
What they will want to hear at the hustings from each candidate, more than anything else, is a credible path to secure the UK's departure from the EU either by 31st October or not long after – and which does not involve either a general election or a referendum. Pretty much nothing else will matter.
But here is the magnificent joke on them and on us. Almost everything that every candidate says in their manifestos to deliver Brexit will turn out to be fiction, if not a deliberate lie – for the simple reason that none can control either a hung parliament or an EU Commission that won't be formed till 1st November.
What Tory MPs and the rest of us will be witnessing next week are auditions for the leading role in the drama entitled 'How Brexit destroyed or saved the Tory Party, and Britain' – and none of us know whether the ending will be happy or tragic.
Robert Peston is ITV’s Political Editor. This article originally appeared on his ITV news blog