Most Republicans do not support efforts to deny Trump the nomination BUT, neither do they think he can beat Hillary. (See the Bloomberg polling results, here).

The most committed Republican voters aren’t rallying behind efforts to deny Donald Trump the party’s nomination at their national convention in July, but he still faces an uphill climb after that.
A Bloomberg Politics national poll shows 63 percent of those who have voted in this year’s Republican primaries and caucuses, or plan to do so, back the billionaire’s view of the nominating process and think the person with the most delegates should win, even if he lacks a majority.
If he emerges as the nominee, the survey also suggests that Trump faces a difficult path to the White House. Hillary Clinton, his likely Democratic competitor, crushes him in a hypothetical general-election match-up. In another troubling sign, Trump is viewed unfavorably by 68 percent of Americans -- well above the 53 percent who feel that way about Clinton. If both make it to the general election, the race would feature two historically unpopular figures as the nominees.
“Trump’s numbers are bad and getting worse,” said pollster J. Ann Selzer, who oversaw the survey. “A majority of Americans now describe their feelings toward him as very unfavorable. That’s a 13-point spike from November 2015.”
In the process, the Republican front-runner may also be tarnishing his party’s brand. Sixty percent of Americans view the GOP unfavorably, easily the highest level recorded in the poll since it was started in September 2009. The Democratic Party, in contrast, is viewed negatively by 43 percent.