Until this morning Jacob Rees-Mogg had had a remarkable Brexit. From being an obscure backbencher he had risen, without any formal position, to being just about the most powerful figure in the Conservative party after the Prime Minister. He controlled a party within a party, influencing the votes of seventy or so MPs. He became the most lucid of all MPs on Brexit, speaking with a logic and clarity which disarmed his opponents. He introduced a term to the debate – vassalage – which identified perfectly the weakness of Theresa May’s deal, and emphasised how the EU had successfully driven the Prime Minister into a corner.

But this morning, all that has gone. In a piece in the Daily Mail, Rees-Mogg has revealed his weak knees as sure as if he were a contestant in a Butlins’ competition. He apologises, as he put it, for changing his mind. He will now vote for May’s deal – assuming, that is, he gets a chance. There is no guarantee that May will be able to bring her deal back to the Commons for a third time, given that John Bercow has said he will block any such motion unless it carries substantial changes from the last such motion. Rees-Mogg says he will do so because, while he still thinks the deal is bad, it is less bad than the alternatives. To read between the lines, he fears, as Theresa May has put it herself, that the choice now lies between her deal or no Brexit – and he wants to leave the EU at all costs.

Yet that doesn’t fit in with his previous pronouncements on the matter, which had argued that May’s deal represents to the worst of all worlds – finding ourselves bound by EU laws but without any say in making those laws. His logic was that a state of vassalage would very much be worse than remaining in the EU – although of course he would far prefer to leave than to stay. Now, he is saying he would rather Britain be a vassal state of the EU rather than be a full voting member. His logic has deserted him, along with his sense of principle.

What we have learned about Jacob Rees-Mogg is that while being an excellent debater, he is an appalling strategist. That was, in truth, revealed last December with his failed coup against May’s leadership of the Conservative party. But now it is confirmed. He has succeeded only in appearing to justify Theresa May’s stubborn approach: keep on banging away at Plan A and refuse to countenance any Plan B. May calculated – correctly as it turned out – that Rees-Mogg would eventually fold if she ran down the clock and raised the possibility of no Brexit. She saw that he so desperately wants to leave the EU that he would eventually grab at anything to achieve this, even at the cost of humiliating himself by voting for what he calls vassalage.

Just because Rees-Mogg has diminished himself, however, does not mean that his followers will all do so. Even if the DUP folds along with Rees-Mogg – as it seems it might well do – there are still likely to be a few hold-outs who will continue to spoil for a no-deal Brexit. In the absence of a majority, the Prime Minister can hardly afford a single one – unless she can turn Labour, perhaps by offering a confirmatory referendum.

Win or lose, May’s premiership is now pretty well at an end. Yet it will have outlasted Jacob Rees-Mogg’s unofficial position as Brexiteer-in-chief, from which he resigned this morning.