LOS ANGELES — Joe Biden’s campaign was nearly declared dead before his resounding victory in South Carolina, but a new string of endorsements and positive polling numbers mean the former vice president could have his best showing on Tuesday, when 1,357 delegates are up for grabs.

The “Never Bernie” movement appeared to get serious on Sunday and Monday, with Sen. Amy Klobuchar and former South Bend, Indiana, Mayor Pete Buttigieg set to back Biden the night before Super Tuesday. Former Senate Majority Leader Harry Reid, a Nevada Democrat, also announced that he was backing the former vice president on Monday afternoon.