Joseph R. Biden Jr.’s lead over President Trump is growing nationwide, but questions about an alleged assault continue to linger, according to a Monmouth University poll released Wednesday. It is the first major national survey to ask voters about the sexual-assault allegations against the former vice president.
All told, 50 percent of voters said they would vote for Mr. Biden in a head-to-head matchup, and 41 percent said they would vote for Mr. Trump. In an April Monmouth poll, Mr. Biden led the president by just four points; in March, he led by three.
After Mr. Biden publicly denied Tara Reade’s accusation last Friday, Monmouth added a question to the poll already in progress, asking whether voters thought the allegation was true. Thirty-seven percent said it was likely credible, 32 percent said it was probably not true, and 31 percent had no opinion.
By two-to-one, independent voters were more likely to say it was true (43 percent) than to say it wasn’t (22 percent).
Mr. Biden was still seen more favorably overall than Mr. Trump: 41 percent of voters saw him favorably, while 44 percent saw him unfavorably. The president was seen positively by just 40 percent of voters, and negatively by 53 percent.
In a hypothetical three-way race with Justin Amash, a candidate for the Libertarian primary election, on the ballot, Mr. Biden still led Mr. Trump — but by seven points, not by nine. Mr. Amash, an independent congressman from Michigan, about whom 81 percent of voters still said they had no opinion, commanded 5 percent in that matchup, including 10 percent of independents.