Here are a few thoughts on what has happened:
(1) There is a gulf between the reactions of the Westminster village and the general public. The villagers are interested in David Davis throwing away the chance to be Home Secretary and what this means for Project Cameron. Most of the public is simply applauding a politician who has resigned his seat on an issue of principle. They’re impressed. DD might soon have the status of his chum, Tony Benn and others like Frank Field, Clare Short and Ann Widdecombe. Big hitting, principled people but not entirely comfortable with conventional politics.
(2) David Cameron called the decision "courageous" but, in many ways, David Davis isn’t taking much of a risk. He’s certain to be re-elected but, on the other hand, he risks not being part of the first Conservative government of the 21st century.
(3) David Cameron’s decision not to appoint an Acting SHS but a permanent replacement in Dominic Grieve shows a ruthlessness from the Conservative leader. David Cameron could have kept the position open. He didn’t. By appointing Dominic Grieve the Tory leader signalled that there’ll be no retreat from the stance that DD has taken on civil liberties. Mr Grieve’s support for the Human Rights Act may mean trouble ahead, however.
(4) What will David Davis do when he returns to Parliament? Accept a more junior shadow cabinet position? Unlikely. He’ll probably go to the backbenches and champion certain causes. David Davis is also a tax cutter. Will he make the case for small government conservatism when he’s back?
(5) How will David Davis keep his campaign in the news? It’s been a massive story today and will lead tomorrow’s newspapers. But, but… Will the campaign stay in the news if DD doesn’t have serious opponents in the by-election? Will he win his contest but on a low turnout? Will this story still be alive on Monday?