An article from The Guardian:

"Rapid studies have found that Kerry's success in winning 11 of the 13 primaries is due not to his innate qualities or his opinions, but that he is viewed by Democrats as the man who can beat Bush.

"When voters in Arizona, Oklahoma, Tennessee and Michigan were asked to set aside the 'can-beat-Bush' factor and think about the issues, Senator John Edwards scored very well indeed, and, as Slate points out: 'Among Republicans and Republican leaners, Kerry's image was on balance unfavourable, while Edwards's image was on balance favourable.'

"So, the desperation of Democrats to be rid of Bush may paradoxically mean that they pick the candidate who cannot attract the swing voters that decide presidential elections."

Read the article here.