Trump's fellow Republicans are fighting to retain the party's majorities in the House of Representatives and Senate.
The five-day poll, which was conducted nationwide, also showed that registered voters broadly favored Democrats over Republicans by 47% to 36% when asked which party they would vote for in what is known as a "generic ballot" question. Some 11% said they did not know who they would vote for if the election were held today.
That gap of 11 percentage points between Democrats and Republicans was 1 percentage point tighter than in a Reuters/Ipsos poll that closed on October 19. The poll that closed on Monday additionally asked undecided voters which party they were leaning toward. Factoring in their responses, the national race appeared somewhat tighter, with Democrats leading by 9 percentage points, 50% to 41%.
For Republicans, losing control of either chamber could complicate Trump's agenda in the last two years of his second term as president.
Generic ballot polls are national polls that provide an overall view of which party poll respondents would like to see in charge in Congress. While these polls provide a view of national public sentiment, they do not capture the nuances of the state-by-state and district-by-district contests that determine control of the Senate and House, contests in which Republicans hold some structural advantages.
The Reuters/Ipsos poll, which was conducted online, gathered responses from 1,679 US adults, including 1,280 registered voters, and had a margin of error of 2 percentage points for all adults and 3 points for registered voters.