So Vince Cable got caught saying he could end the coalition. The genuinely interesting point here is that, surprisingly, the coalition has failed to end Vince Cable. Clearly this is a significant reduction in his status, but it’s surely beyond doubt that any minister who, rather than resigning if they disagreed with the cabinet, instead generally threatened to resign as a way of extracting concessions politically would be in trouble. It’s the prime minister’s prerogative to make and unmake ministers as the agent of the Crown, subject to the confidence of Parliament. Simple.

So the fact that he’s still there is non-trivial; we know that the prime minister is not, in fact, entirely free to dispose of ministers as he wishes. It seems to be an emerging theme that the coalition gives the Lib Dems more power over personnel politics than it does over policy.

We’re late to the party with this, but a couple of points. First of all, there’s nothing new about the idea of a ministerial “quasi-judicial” status; this concept has been knocking around for years. I remember it from the 1990s. Cable should surely have realised this might be an issue. As so often, the most penetrating analysis comes from the Daily Mash:

But as Mr Cable's underlying cretinosity was joyfully exposed, millions insisted they had never heard of him and even if they had they would certainly never have described him as the 'sage of Twickenham' at a succession of dinner parties where everyone agreed with them enthusiastically....Cook added: "I suppose it's a bit like St Peter denying Jesus three times before the cock crowed. Except of course that Jesus was Jesus and Vince Cable is just some daft old bugger with a column in the Mail on Sunday - which, by the way, should have been a huge fucking clue..."Still, he will love being compared to Jesus."

Secondly, it’s very telling that the issue of quasi-judicial status works for people who disagree with Rupert and doesn’t for people like Jeremy Hunt who do agree with him. That’s how power works.

Thirdly, we’re far from sure the Torygraph’s sting was defensible. If MI5 is constrained to respect confidentiality between MPs and constituents, under the Wilson doctrine, it’s hard to argue that nobody else is. And if one side of the conversation (constituent to MP) is confidential, how could the other not be? You can’t easily avoid learning the other half of the conversation while spying on it, and you can certainly deduce quite a bit of one from the other.

Also, if you wanted to bully the MP politically to, say, stop asking difficult questions about a terrorist suspect, you’d want to know the suspect was talking to them, period. Detail would be nice-to-have. Further, the basic headline here is “Man Has Opinion, As Is His Legal and Moral Right”, and are we really short of insincerity in politics?