The allegation is that Green received a series of leaks embarrassing to the Government from a Home Office official, which later appeared in the media. His home and offices were searched by counter-terrorist officers, as was his office in the Houses of Parliament. And this final point is, I think, the focus of the shitstorm.
Had the police phoned Green up and asked him to go to the nearest police station, and had they not searched his office at Westminster, I don't think there would be the cross-party fury about the incident.
Green and David Cameron have both come out fighting, saying that Green had made public some information which was in the public interest but the government found uncomfortable.
What has barely been touched upon is that a week or so ago a junior Home Office official was arrested in connection with this and suspended from duty. There was no shitstorm about this. Nobody stood up on television to defend this person who had helped make public some information which was in the public interest.
What the Green affair is all about is Parliamentary privilege. Some quotes are instructive. Tony Benn, that grand old madman, said today, "I may sound strangely medieval, but once the police can interfere with parliament, I tell you, you are into a police state. Parliament is a safeguard against the abuse of power and once you start clamping down on it you are saying goodbye to the freedom that parliament gives you."
Denis McShane, a former Labour minister, said, "To send a squad of counter terrorist officers to arrest an MP shows the growing police contempt for Parliament and democratic politics. The police now believe that MPs are so reduced in public status that they are fair game for over-excited officers to order dawn raids, arrests and searches of confidential files held by MPs or those who work for them. I am not sure this is good for British democracy."
The government, predictably, has run for the hills. Gordon denied knowing anything about it, saying, "I had no prior knowledge. The home secretary had no prior knowledge. I know of no other minister who had any prior knowledge. I knew about it only after it had happened when I was told by the permanent secretary to the civil service that this had happened." In other words, it's starting to go pear-shaped, blame it on Plod.
This sort of gibes with the fact that, apparently, the Speaker of the House of Commons, David Cameron, and - rather confusingly - Boris Johnson, were all given warning that the raids were going down. And nobody mentioned it to the Prime Minister? The Leader of the Labour Party? Hm.
What we're seeing now is MPs reacting, not to the fact that Damian Green has been arrested and his office searched, but that one of their number has been arrested and his office searched, and if it can happen to him, it can happen to them too. If it turns out that the Speaker gave permission - however tacit - for the search at Westminster to go ahead, there will be hell to pay.
And now it turns out that the Tories filmed the police raid on his Westminster office.
Damian Green ought to think himself lucky. Other people who've tangled with the Organs Of Security have wound up shot.