David Cameron's political antennae have badly let him down over phone hacking. It is an important moment for his premiership, although not, perhaps, a Titanic-on-the-iceberg moment, as some commentators  have implied.
Naturally, he was cosy with News International. That, sadly, goes with the territory of being PM. So the fact of courting Rupert Murdoch and Rebekah Brooks was not so much a matter of judgment as submission to perceived political necessity. That doesn't make it OK - there will be much cringing in No. 10 over the photos of Cam and Brooks looking chummy. But the fact of a relationship is not, in itself a personal blow to the PM. The NI power game is a cross-party issue in the Westminster. The Labour party (as Mehdi wrote this week ) is hardly immune from criticism on that front.
It is the appointment and repeated defences of Andy Coulson that make this whole issue toxic for Cameron. Presumably, when the appointment was first made in 2007 - on the recommendation of George Osborne, let no-one forget - a conversation was had about the existence of skeletons in NoW closets and how they might, in the future, damage the party and its leader. How thorough was that conversation? Was it repeated when the Guardian first started exposing the scale of the hacking, by which time Cameron was PM and Coulson was a senior figure in the government? Whatever happened between them, Cameron must not have interrogated his advisor enough about the culture of hacking and paying the police at the News of the World. Or he did and Coulson lied to him, in which case, shame on Cam for believing him.
There is always, of course, the possibility that Coulson was sincerely ignorant about what went on in his newsroom, in which case, as has been observed before, he would have to confess to being an incompetent idiot instead of a villain. My sense of it, based on a handful of encounters with Cameron and conversations with people who know him is that the prime minister has a blind spot when it comes to accusations against people who are useful to him. There is an instructive comparison to be made with the row around Lord Ashcroft's tax status  that blew up just before the election.
Cameron let William Hague take the heat over that mini-scandal and it didn't get much public notice. It was nevertheless interesting how tetchy Cameron would get when asked about it in interviews and briefings. He had two stock responses. First, no-one cares about this apart from a handful of Guardian hacks. Second, this is all politically motivated and partisan and all of the supposed outrage about tax avoidance is confected by people who really just want to kick me and the Tories. Sound familiar?
That has been Number 10's default response to the phone hacking scandal. Cameron was intensely relaxed about it until recently for the simple reason that ordinary voters didn't really know what it was all about. The Downing St switchboard was not lighting up with complaints about Andy Coulson. That reinforced the prime minister's feeling that the whole thing was a Labour ploy to damage him, using Coulson's reputation as the weapon. That brought out Cameron's mulish side. He calculated that the political risk involved in keeping Coulson on board for so long was smaller than the risk of being seen to capitulate to a lefty plot.
What was entirely missing from these calculations was any understanding of why people might, as a matter of genuine principle, think it is wrong to hack into the voicemail of private citizens, just as I don't think he ever thought people were that sincerely outraged that Ashcroft avoided UK taxes while sitting in the Lords. In other words, he treated it as a political poker game, not an ethical choice. Only now that the hacking scandal has taken in victims of crime and families of bereaved soldiers does he begin to understand that it was an appalling practice *per se* - and not just something that Labour MPs said was appalling because they don't like being in opposition.
But it's too late for him to affect moral outrage. He can try, of course. But he left it too long. He should have been naturally disgusted that a national newspaper had clearly been operating a kind of sleazy Stasi approach to newsgathering, but he clearly wasn't. That was a pretty serious lapse of political instinct. My guess is that Conservative MPs - and the PM himself - will be a bit shaken by that. The mark of a good leader is that he can smell the way the public mood will go on something and leap accordingly. Leadership fail.