The short answers are:
1. MPs have the power to block a no-deal Brexit
2. The likelihood of them permanently and definitively blocking a no-deal Brexit is slim-to-none
Here is why, if you can be bothered to read on.
First of all, MPs have already demonstrated that they have the power to take control of the Commons order paper, and then legislate to mandate the PM to sue the EU for a further Brexit delay or to remove a no-deal Brexit as the legislated default position in the event that a negotiated Brexit cannot be achieved.
Second, they have the power to bring down the Government by a vote of no confidence, install a temporary government of national unity and then sue the EU to postpone the date we leave the EU.
So yes, MPs have the power to block a no-deal Brexit.
But the reason they won't is that - under the British Parliamentary system - the opposition is (almost by definition) a disorganised rabble.
When I talk with those at the top of the opposition parties, I hear contradictory and confusing views - a cacophony of madness - on whether to try to legislate to force Johnson to take no-deal off the table or to vote to replace him with a unifying, anti-no-deal PM.
Unless MPs can coalesce around a simple single strategy, Johnson and his most important aide Dominic Cummings win: the UK will be out, sans EU settlement, on October 31.
But Labour, the SNP and the Lib Dems all have their own ideas about how to stymie Johnson. And they will not and probably cannot hunt in a pack.
In that context, the most important statement by John McDonnell, the shadow chancellor, on my show on the day that Johnson was crowned as PM - which weirdly feels a lifetime away but is actually less than a fortnight ago - was that Labour had absolutely zero interest in participating in a government of national unity.
There were no ifs or buts. He was categoric.
Labour would form its own government under Jeremy Corbyn or Johnson would stay, he implied. And it is almost inconceivable that Corbyn can win enough backing from rebel Tories, as well as the other opposition parties, to command the confidence of the Commons.
There is only the remotest chance of Labour rallying round Ken Clarke or Jo Swinson as possible anti-no-deal PMs for however long or short would be needed to persuade the EU to provide a further extension of our membership of the EU.
And as for MPs seizing control of the order paper, if that prospect were to loom Johnson would call Labour's bluff, say he wants a general election and dare Labour and other opposition parties to refuse his request - which I cannot conceive they would ever do.
Most paths seem to lead ineluctably to the people having the final say on whether the UK leaves the EU without a deal or whether it remains in the EU - but a final say through a general election rather than in a referendum.
And again, if you share my logic, Johnson probably wins - either because he succeeds in rigging the election timetable such that the new government cannot be formed till after the UK has left the EU on October 31, which is a prospect I regard as unlikely, or more likely because there is absolutely zero sign of Corbyn offering voters the necessary simple choice between a Tory party that would remove the UK from the EU, no ifs or buts, and a Labour party that would keep the UK in the EU.
Instead, and according to senior Labour forces, Corbyn seems wedded to the latest iteration of its complicated policy, which is to promise a further Brexit referendum.
And if voters were presented with a clear Tory policy to take the UK out of the EU without a deal, but an opposition divided between Labour hinting there could be a form of Brexit it might support and that in any event there must be a referendum, while other opposition parties were saying they would prefer simply to stay in the EU, then left-of-centre voters would understandably be muddled and anxious about who to support.
And if left-of-centre voters are disunited and unsure whether to vote for Labour, or Lib Dem or Green or Plaid or SNP, Johnson scoops the prize.
By the way, Johnson and Cummings are acutely aware that a referendum is much more dangerous for them than a general election.
Because in a referendum, the Remain side would be united and coherent - whereas in a general election the anti-no-deal opposition would be engaged in internecine warfare that would consume them and turbocharge Johnson back into 10 Downing Street.
So I am not surprised that Johnson and his colleagues seem as confident as they do.
And I am mildly surprised that the People's Vote campaign has not reinvented itself as an umbrella organisation to coordinate anti-no-deal voting in the seemingly imminent general election, rather than as cheerleader for a plebiscite that has vanished beyond the horizon.
Here is the fundamental reason why a no-deal Brexit is now overwhelmingly likely: senior officials in Brussels and in European capitals tell me that there is no basis for negotiating a new Brexit settlement with Johnson - which is almost a truism - and that broadly the choices are between a near facsimile of May's settlement, remaining in the EU or a no-deal Brexit.
They then add, which they see as a total truism, that at this juncture only the Commons can block a no-deal Brexit by usurping Johnson.
Do they have faith MPs will block no deal?
"The case is hopeless," said one - whose corollary, for better or worse, is that Boris Johnson's no-ifs-or-buts, do-or-die Brexit may be a locomotive on which the brakes have been removed.