Could Kamala Harris be a winner for the Democrats if Biden steps aside?

The vice-president would be a logical choice if Biden does opt out, but some are already looking to other contenders

Joe Biden's stumbling debate performance left Democrats so panicked some are searching for an alternative to replace the 81-year-old president as the party's standard-bearer.

Biden has given no indication that he intends to exit the race, and his campaign has flatly dismissed the suggestion. But that has done little to silence critics who are openly questioning whether Biden is the right person to take on Donald Trump, a figure the president - and his party - view as a grave threat to American democracy.