Mr McCain could be the perfect candidate for this new mission. He is less bound by old orthodoxies than almost any other national Republican. He fought Mr Bush and Donald Rumsfeld, the former defence secretary, on Iraq strategy, and has been proved right while they have been proved wrong.

Unfortunately, Mr McCain has been a maverick on issues that matter least to voters: campaign finance reform, tobacco, climate change. On the ones that matter most to voters – healthcare, economic management, immigration – he has positioned himself with party orthodoxy and against the voters.