US President Donald Trump is more popular with likely voters than he is with the general public, according to a new poll.
The Reuters/Ipsos poll underscores why Republican lawmakers have largely stuck with the polarising president despite his plunging approval ratings.
The survey, released on Wednesday, shows he polls better among people who voted in the 2016 presidential election than with the overall US adult population - a group that includes both voters and non-voters.
Only about 60 per cent of the voting-age public took part in last year's election.
In October, for example, 44 per cent of 2016 voters said they approved of Trump's performance in office, compared with 37 per cent of the general population.
Among Republicans, 82 per cent of voters approved of Trump in October, compared with 75 per cent of all Republicans.
Some 85 per cent of those who voted for Trump in 2016 said they would do so again, the poll found.
The findings suggest that Republican candidates in the 2018 congressional elections who shun the president risk alienating his followers, Republican strategists and political scientists said.
At the same time, those who embrace him in the early primary races that choose party candidates risk losing moderate voters in the general election.
"It's very difficult for any Republican candidate to distance themselves from Trump," said Michael McDonald, an expert on voter turnout at the University of Florida.
That dilemma played out in Virginia on Tuesday, when Ed Gillespie, the Republican candidate in the governor's race, was soundly beaten by his Democratic opponent.
Gillespie had adopted some of Trump's hardline positions but had avoided campaigning with the unpopular president.
Gillespie's strategy had been closely watched within the party to see if it could provide a template for other Republican candidates in 2018, when control of the House of Representatives and the Senate will be up for grabs.
