Who might replace Biden on the top of the ticket?

President Joe Biden's stumbling performance in the debate against former President Donald Trump has some Democrats raising the possibility of nominating an alternative candidate and mulling over a roster of names. High on the list is, of course, Vice President Kamala Harris, whose status as Biden's running mate might make her an easy candidate for delegates to turn to during a difficult moment. But a crop of Democratic governors and other figures are often mentioned, too.

A candidate switch would most likely require Biden to step out of the race, something his campaign says he has no intention of doing. And the risks are real. Some of the highest-profile potential stand-ins listed below have never endured the vetting and road test of a presidential race. There is a long list of candidates who looked great on paper and withered on the campaign trail.

"It's not as easy...