So, now that the dust has settled, what are to make of it all? The news media is in meltdown mode as they struggle to come to terms with the enormity of what David Davis has done. Instant conclusions are naturally being drawn, but many of them are very detached from reality.
I should perhaps make clear that I did not know about this decision until this morning. I am glad I didn't for several reasons. I still haven't spoken to him so what I am about to write is my take on the situation and my take only.
During my six months working for DD in 2005 Tony Blair's 90 day detention proposals I saw first hand how passionately he feels about this issue. It's not a matter of political conviction, it's almost as if it is in his DNA. He genuinely thinks that extending pre charge detention to 42 days will make the country less safe. It will give the terrorists a propaganda victory.
Up until the weekend he believed the 42 day proposal would be defeated. He hadn't reckoned on the duplicity of the DUP or the fact that so many Labour MPs would be bought off by offers of goodies for their constituency or the chairmanship of this or that committee.
Labour is spinning away that David's decision is a kind of emotional reaction to the loss. They could not be more wrong. David Davis doesn't make emotional decisions. He makes them with a military precision. He won't have done this on the spur of the moment, he will have thought about it deeply and played some war game scenarios. In the end he will have come to the conclusion that the only way to defeat the 42 day agenda is to start a massive public debate. And that's what a by election will do.
This isn't about one man's vanity. It is about the ability to sacrifice personal and public advantage for a greater cause. As he said in his statement, Sunday is the anniversary of Magna Carta. Over the last 800 years people have fought and died to protect our civil liberties. If it falls to one man to sacrifice political advantage to try to make a stand against their further erosion, then so be it.
David would have been Home Secretary in the next Conservative government. He has consistently been the party's best media performer over the last two years. He has played a major part in the revival of Conservative fortunes, and while many people have tried to drive wedges between him and David Cameron they have failed to manage it. Quite obviously, they come from a different background and have certain different priorities - so do any two politicians. But during the leadership contest they grew to respect one another greatly and a good working relationship was established. For David to sacrifice his political future in this way, effectively to be a single issue campaigner, says a lot about his moral compass.
I don't pretend that David Cameron will be pleased at today's turn of events. He would obviously have wanted to keep David on board. But he is where he is. We are where we are. How's that for being profound!? He's made an excellent appointment in Dominic Grieve, someone who regular readers know I believe should have been in the Shadow Cabinet ages ago.
The LibDems are to be commended for deciding not to stand in the by election. Labour is showing all the signs of following suit. If they do, they will be treating the issue (and voters) with contempt. The 42 day issue can now be debated fully during the by election campaign. Sure, there are 69% of people opposed to David's stance, but they oppose it with their hearts not their heads. Most of us can have sympathy with banging terrorists up for as long as it takes, but when you think about the actual consequences of doing so without charge, you slowly begin to think with your head, not your heart.
I see that well know by election Labour campaigner, Stephen McCabe MP, thinks that David is "treating Parliament and the voters with contempt". They really don't get it, do they? They don't get the fact that our there, voters are crying out for politicians who take moral stands and stand up for what they believe in, even if it is temporarily unpopular. They are fed up with politicians who are on the take, or can be corralled into a voting lobby by a government whip offering them sweeties for their pet cause. Ann Widdecombe made a courageous stand when she made her something of the night speech. She did so in the full knowledge that it could be the ruination of her political career. She did what she thought was right. And that's what David Davis is doing.
So what now? I have been inundated with emails from people offering David help for the by election, and also money. Facebook groups have already been formed in his support.
As many of you will have seen, I have been on various media outlets during the afternoon giving my views. It's been like flying blind to be honest. Dangerous but fun!