What to expect on night one of second Democratic debate

Twenty White House hopefuls will take the stage at a crucial point in the Democratic primary.

For well-known candidates like Beto O'Rourke and Joe Biden, it offers a do-over following widely panned performances in Miami.

But for struggling White House hopefuls, it could be a last chance to breathe life into a campaign before tougher debate qualification rules kick in that are all but certain to thin the field.

The Associated Press has contributed to this report.