This morning I'd have bet my bottom dollar that Theresa May would appoint Britain's first female Defence Secretary to replace Michael Fallon.
Instead, she replaced him with a man – and not just any man: Gavin Williamson. The MP who, as Chief Whip, probably knew more about the cosseted world of Westminster and was until today the keeper to its secrets, including the sexual misdemeanours of his colleagues.
Overnight there had been much feverish speculation that with Fallon's resignation and her de facto deputy Damien Green's potentially in the offing, May might have to resign.
I thought this was ridiculous on both moral and political grounds.
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Morally – unless it could be shown that May had directly concealed evidence of sexual harassment personally – it would seem outrageous that a person who has never been involved with sexual harassment, much less a female prime minister, should lose her premiership over the actions of men for which she has no responsibility.
People might say she knew these things took place but she is no more no less responsible for that than anyone senior who works in Westminster.
Gordon Brown didn't resign over expenses, despite being PM at the time, because his reputation was beyond reproach. May should be held no more culpable than he was.
Politically, it struck me that far from having to resign, May had the potential to emerge from this morass much strengthened.
Many of her key rivals might become mortally wounded by this crisis. And many MPs, otherwise despairing of May's overall performance, might have been counting their lucky stars that although she might need the odd cough sweet to get through a speech, they have her after all.
Imagine if they'd opted for last year's leadership candidate Stephen Crabb, who recently had to apologise for sending "explicit" texts to a 19-year-old woman. A sexual scandal at 10 Downing Street's door.
But in this one move, May has been drawn into the morass.
Williamson and the PM had already come in for some criticism for not doing more to crack down on the misbehaviour and reveal what they knew.
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Now that focus will become much, much sharper: What did Williamson know? Had anyone approached him with accusations and what did he do about it? And worst case scenario: did he use the knowledge of sexual misdemeanours to exercise power over an MP in exchange for the party's help in ensuring they never became public?
Every journalist in Westminster will now be working on these questions. It will be the PM's judgement in appointing him in the firing line.
Politically, it is also extremely curious. May clearly wanted to reward Williamson's loyalty (he ran her leadership campaign) but to remove the Chief Whip at a time when she is trying to get Brexit legislation through Parliament during a minority government is bizarre.
She didn't even make the best of it and replace Williamson with a woman – despite many Tory MPs to claim the first female Chief Whip came from their party.
That person would have been a strong signal that the Whips' operation – and by extension the way Westminster works – had changed.
Instead the PM appointed Julian Smith, Williamson's erstwhile deputy. Worthy appointment he may be, but hardly one which makes even the weakest of political ripples.
And then there's the reaction of her backbenchers. One word: incredulity.
Many MPs are astonished that a man with no departmental experience has been promoted to one of the most important Cabinet jobs.
There is also anger that he appears to have removed Fallon only to effectively appoint himself. As one senior Tory backbencher texted me: "He's out of the s***storm. He knifed Fallon and pinched his job. He's never spoken at the despatch box. It's way, way above his ability."
If the knives do come out for Williamson, he may find few allies to defend him.
In some ways this story so far has been eminently predictable. The characters involved, the misdemeanours, the fact that post-Weinstein it happened at all has come as not much surprise to Westminster.
Today was the day that changed and the runes became almost impossible to read. And for a Prime Minister one major crisis away from resignation, surprise is the last thing she needs.
