A Change Research poll released this week offers some clues. It showed Biden well ahead of his potential Democratic rivals in South Carolina, which is expected to vote fourth in the Democratic primary process. (The survey was conducted March 31-April 4.) Thirty-two percent of Democrats said they favored Biden, with Bernie Sanders (14 percent) and Kamala Harris (10 percent) the only other candidates in double digits. Of course, that Biden is leading in South Carolina is not surprising — he leads in basically all polls of the 2020 field, nationally and in the early primary states.

But Change Research also conducted a version of the poll with only declared candidates — leaving out Biden and other potential late entrants1 And that showed a much different, more wide-open race. Sanders was in first with 24 percent, and five other candidates were in double digits: Beto O’Rourke (16 percent), Harris (15), Cory Booker (12), Pete Buttigieg (12) and Elizabeth Warren (11 percent).

This poll, like all polls at the moment, should be treated with caution. It’s very early, this is only a single state and some of the support for Biden and Sanders probably reflects that they are the most well-known of the candidates.