National poll - The former Vice President Biden fares best against Trump in the early head-to-head surveys. He leads the incumbent by a 50% to 44% margin, the poll found.
Sen. Bernie Sanders, I-Vt., has a 4-percentage point advantage, 49% to 45%. Sen. Elizabeth Warren, D-Mass., leads 48% to 45%.
Former South Bend Mayor Pete Buttigieg has a 1 percentage point edge, 46% to 45%.
Biden, Sanders and Warren all hold smaller leads over Trump than they did in a December survey.