The party Mr Johnson wants to lead, The Conservatives, seems hopelessly divided. Last night Mr Cameron had to rely on the Labour Party to get his legislation, on gay marriage, through.
I don't think it is impossible for the Tories to recover - they have emerged from such schisms before - but nor do I think, as some newspapers have suggested, that they are 'split down the middle'. It seems to me that the activists and supporters, the party in the country, know pretty well where they stand, on marriage, Europe, immigration and so on, and that their representatives in parliament are by and large in the same place (it should be noted that whilst there have been rebellions of around half the parliamentary party, the large numbers of cabinet and junior ministers, PPS's and bag carriers, known as the payroll vote, aren't allowed to rebel, even if they think the same as the rebels).
What is splitting the party is Mr. Cameron and a small coterie of advisers who are closet social democrats. Cameron was doubted by many in 2005 but made leader because they thought he was a winner. In the 2010 General Election he missed the greatest open goal in political history and seems to be celebrating this feat by going off on a frolic of his own, employing as party chairman an old university friend who thinks the party's supporters are 'swivel-eyed loons'.
There is, just, time to get rid of Mr. Cameron, although I suspect that his obvious replacement, Mr Johnson (see below) might be found out within a few months. Probably their best bet is to go into the election with their fingers crossed and afterwards have a good clear-out. Philip Hammond, the Defence Secretary, is my tip.