Biden's wall of support for his re-election bid began to crumble, as a Democratic senator called for him to exit the race, a party heavyweight indicated his candidacy remains an open question and a Hollywood donor said he can't win.

Biden’s wall of support for his re-election bid began to crumble, as a Democratic senator called for him to exit the race, a party heavyweight indicated his candidacy remains an open question and a Hollywood donor said he can’t win.