President Trump is trailing Democrat Joseph R. Biden by 10 percentage points in a poll often cited by the president as being fair to him.
The Rasmussen Reports survey released Wednesday shows Mr. Biden, the presumptive Democratic nominee, leading the president, 50% to 40%.
Nearly one in five Republicans in the survey, 19%, said they would vote for Mr. Biden today. Among the GOP, Mr. Trump is winning 74%, far below the 96% that the president often cites as his level of support in his party.
The president tweeted on Wednesday in all capital letters, “The silent majority is stronger than ever, just watch!!!”
Mr. Biden has the support of 79% of Democrats in the Rasmussen poll. Voters not affiliated with either party favor Mr. Biden 48% to 36%.
The Trump campaign has said many public polls undercount support for the president, and that its internal polling shows the president performing well against a “defined” Mr. Biden.
