According to the newly released data, Biden has the support of 31 percent of black Democratic primary voters, while Sanders captures the backing of 29 percent.

The NBC News/WSJ poll used an oversample of black voters to gain greater insight into their views of the 2020 field. Because the margin of error for black Democratic primary voters alone — a sample size of 139 respondents — stands at a high 8.31 percent, it is difficult to differentiate the true levels of support for each of the candidates.

Still, the close margin shows that Sanders has made inroads in a community previously dominated by Biden; aggregated data from 2019 shows that Biden led Sanders among these voters by as much as 30 percentage points in NBC News/WSJ national polls last year.