Cameron's self-image as social reformer challenged to the core by personal attack
In a sense, David Cameron owes his job to Iain Duncan Smith. Without the abject failure of Mr Duncan Smith's leadership between 2001 and 2003, the Conservatives might not have reached the collective conclusion that a traditional Tory focus on issues such as Europe would not win an election and realised that, to use a Cameron phrase, they had to change to win.
Mr Cameron's leadership is easily understood as a political reaction to Mr Duncan Smith's, but the two have more in common than is easily visible. Intellectually, there is a continuity between the two leaderships that is not often realised. Even as he was failing dismally as leader, Mr Duncan Smith was saying things about the party that Mr Cameron would endorse.
So in his awful 2002 "quiet man" speech to the Conservative conference in Bournemouth, we find IDS outlining a vision of "compassionate conservatism", declaring: "We believe that the privileges of the few must be turned into the opportunities of the many."