Biden continues to lead among African-American Democratic primary voters, but his support has declined from 52 percent in January to 38 percent now, while Sanders’ backing among these voters has remained steady in the 20’s.

Bloomberg’s support among African Americans has doubled from 9 percent last month to 18 percent now.

“Biden’s support with African Americans is under assault,” said McInturff, the GOP pollster.

When the Democratic field is reduced is just Sanders and Bloomberg, the Vermont senator holds a 20-point national lead over the former New York City mayor, 57 percent to 37 percent.