The man who served eight years as vice president under President Barack Obama, 76-year-old former Delaware Senator Joe Biden, has led the Democratic field in almost every poll since he announced his candidacy on April 25. In a new poll of "likely" Democratic voters released on Saturday by HarrisX, Biden appears to have expanded his lead to its widest margin yet: 23 percentage points.
The HarrisX poll of likely voters shows Biden commanding 36 percent of the nationwide Democratic vote in the primary race, with Vermont Senator Bernie Sanders and Massachusetts Senator Elizabeth Warren his closest competitors, each tied at 13 percent of the vote.
The poll also surveyed registered voters, not all of whom consider themselves "likely" to vote in a primary election. Among registered voters, Biden, at 31 percent, held a still-impressive 17-point lead over Sanders, as reported by FiveThirtyEight, and a 20-point lead over Warren. California Senator Kamala Harris places fourth with just 7 percent support among registered voters, and 9 percent among "likely" voters, according to the new poll.
Perhaps most crucially, however, the poll showed Biden with a commanding 19-point lead among registered black voters, with 36 percent to 17 percent for Sanders. Harris, who is herself one of only two African-American candidates in the race, places third with 11 percent of black voter support. Warren commands only 6 percent, tying her with New Jersey Senator Cory Booker, the second of the two African-American candidates in the Democratic field.
Winning among African-American voters has been a key to winning the Democratic nomination since 1992. In each of five competitive presidential primaries — that is, those without an incumbent Democratic president running effectively unopposed — the candidate who won the majority of the black vote went on to win the nomination, according to an NBC News report. Most recently, in 2016, Hillary Clinton captured 77 percent of the black vote.
The black vote could be more important in 2020 than in any previous election, according to the NBC News report, because in 2016, black voters comprised a record 24 percent of the Democratic primary electorate. That percentage is expected to rise and set a new record in the 2020 primary race.
Biden also continues to lead in the average of all polls compiled by RealClearPolitics, holding a solid 11.8 point margin over Sanders and 12.4 points over Warren.
One Monmouth University poll earlier this week showed Biden in an effective three-way tie with Warren and Sanders, at 19 percent support to 20 percent each for the two senators. But Monmouth's polling director quickly disavowed his own poll as an "outlier," as CNN reported.