Among all registered voters, Biden has the highest favorability, with Warren not far behind.

Democrats and Democratic-leaning independents, however, prefer Warren at a higher rate.

Source: NPR/PBS NewsHour/Marist Poll of 1,317 U.S. adults conducted Sept. 5-8. The first chart's data reflect the 1,160 respondents who were registered voters, with a margin of error of 3.8 percentage points. The second chart's data reflect the 542 respondents who were registered Democrats or Democratic-leaning independents, with a margin of error of 5.6 percentage points. Totals may not add up to 100% because of rounding.

Credit: Daniel Wood/NPR