David Usborne: Capitalist credentials will decide contest

Democrats who believe that Mitt Romney will be the Republican nominee this year calculate that one word may end up deciding his match-up with Barack Obama. It is Bain.

Bain Capital, the private equity firm Mr Romney co-founded, has thrived by making faltering firms more profitable, an honourable pursuit in this land of capitalism. But Mr Romney will not be the only one interpreting what his Bain experience means.

The party that comes up with the most convincing Bain narrative wins the White House. For Mr Romney, the US economy is faltering too and he knows what needs to be done to get it purring.

Surprisingly the Battle of Bain is already upon us thanks not to Democrats but to Republicans Newt Gingrich and Rick Perry. If they can use it to hurt Mr Romney, so can the Democrats.