Other than a 2-point bump last week for Sen. Elizabeth Warren (D-Mass.), Biden’s the only candidate to increase his share of the vote in the past two weeks, with others stagnating or dropping. Sanders – who’s polling second with 19 percent – is down 5 points since Biden’s April 25 announcement, while South Bend, Ind., Mayor Pete Buttigieg is down 3 points over the same time period.

Biden leads Sanders by 24 points, 44 percent to 20 percent, among likely Democratic primary voters in Iowa, New Hampshire, Nevada and South Carolina — the first four states to hold nominating contests.