Only 71 percent of Republicans and independents who lean that way would vote for Trump if he were to face Hillary Clinton in a general election; 8 percent would vote for Clinton, 10 percent for another candidate and 10 percent would not vote.
In the less likely scenario that Vermont Sen. Bernie Sanders is the Democratic nominee, 70 percent would vote for Trump, 13 percent would vote for Sanders, 10 percent for another candidate and 8 percent would not vote.
Despite the reluctance among some Republicans to support Trump, he was the most popular GOP candidate among the poll's more than 1,100 respondents: 37 percent said they want Trump to be the Republican nominee compared to 22 percent who want Texas Sen. Ted Cruz, 18 percent who want Florida Sen. Marco Rubio and 9 percent who want Ohio Gov. John Kasich.
Many of the respondents who support someone other than Trump are not under any illusions that their preference will win: 72 percent predicted Trump will secure the nomination, compared to 11 percent who predicted Cruz and 4 percent who predicted Rubio.
A majority of respondents – 56 percent – said they are satisfied with the field of Republican candidates, while 35 percent said they would like someone else to receive the party's nod.
For that to happen, the candidates would have to fail to win the 1,237 delegates needed to clinch the nomination, and the delegates would have to coalesce around an alternative nominee. Asked if House Speaker Paul Ryan, R-Wis., would make an acceptable nominee in that scenario, 40 percent of respondents said yes.
There are definitely some people speculating, even hoping, that a brokered convention could lead Paul Ryan to run. On Thursday, David Satterfield, a D.C.-based campaign finance consultant, filed papers with the FEC to start a super PAC called Committee to Draft Speaker Ryan.
Ryan's lawyer Timothy E. Kronquist wrote a letter to the FEC on Friday formally disavowing the super PAC.
"Speaker Ryan has repeatedly announced publicly that he is not running for president in 2016," Kronquist wrote. "It is the speaker's sincere hope that donors and supporters are not confused by, or misled into supporting, this organization."
Ryan, the former Republican vice presidential candidate, decided not to run for president in 2016 because he wanted to chair the House Ways and Means Committee, which he did for about nine months before he was elected speaker.
A whopping 82 percent of respondents think Ryan did the right thing in staying out of the presidential race. And it doesn't appear that's because they don't like him; 53 percent said they have a favorable opinion of Ryan.
However, they seem to like the current candidates just a little bit better – Trump and Kasich had a 56 percent favorability rating, Cruz's was 57 percent and Rubio's was 59 percent. Ben Carson, who's ending his campaigning, had the highest favorability rating at 73 percent.
The Economist Group/YouGov poll was conducted March 2-3 and has a margin of error of plus or minus 3.3 percentage points. Data reflect responses from 1,116 Republicans and independents who lean Republican. CQ Roll Call is part of The Economist Group.
— Lindsey McPherson, CQ-Roll Call