Democratic governors reportedly waiting in wings after dire Biden debate

Biden campaign launches counter-offensive amid fears that frail appearance at debate could mean defeat in November

With the White House scrambling to prevent Joe Biden's candidacy being enveloped in a full-blown crisis, several state governors were said to be subtly positioning themselves as late substitutes while avoiding being seen to do so.

The Biden campaign has launched a counter-offensive, including furious networking among senior Democrats, to counteract fears that the 81-year-old president's frail appearance in last week's debate had made defeat at the hands of Donald Trump in November's election inevitable.