Beneath the solid, wise-guy exterior Vince Cable likes to display to the world there's always been a less impressive, rather vain man struggling to get out. Someone who shows off when he does not need to, who is less firm of purpose than he pretends and who infuriates colleagues, including Nick Clegg, who has never been a fan.
A couple of years ago, when Cable was being worshipped by the nation as the man to get Britain through the economic storm, those who knew him better already had their doubts. It's this sustained distrust that counts against him now, much more than the one-off idiocy of boasting to a pair of undercover Telegraph hacks. No one in Downing Street will be begging Cable to stay, as they did David Laws, though they need him, which is why it appears that he will survive in the cabinet in some form.
Cable is one of those men best respected at a distance. He is flakey, in a way that's quite bizarre in such an experienced and intelligent man. The Lib Dem strategy for power involves the party proving to voters that it can be professional – that government is better when Lib Dems are involved. Cable's behaviour rips that plan apart.
http://www.guardian.co.uk/commentisfree/2010/dec/21/vince-cable-lib-dem-strategy