Alarmed by the harsh attacks and negative tone of their presidential contest, broad majorities of Republican primary voters view their party as divided and a source of embarrassment and think that the campaign is more negative than in the past, according to a New York Times/CBS News national poll released on Monday.

The dismay has not set back their leading candidate, however. While about four in 10 Republican voters disapprove of how Donald J. Trump has handled the violence at some of his rallies, Mr. Trump has also picked up the most support recently as several rivals have left the race. Forty-six percent of primary voters said they would like to see Mr. Trump as the party’s nominee, more than at any point since he declared his candidacy in June. Twenty-six percent favored Senator Ted Cruz of Texas, and 20 percent backed Gov. John Kasich of Ohio.

Fully three-quarters of Republican primary voters expect Mr. Trump to be their party’s nominee.

Compared with Republicans, far more Democratic primary voters see their side as unified and say the campaign has made them feel mostly proud of their party.

Yet Democrats are more sharply divided over their candidates. Hillary Clinton has only a slight edge over Senator Bernie Sanders of Vermont, and growing numbers of Democratic primary voters are more excited about Mr. Sanders as their possible nominee. In the past month, the level of enthusiasm for Mrs. Clinton among Democratic voters has fallen eight percentage points to 40 percent, while it has grown for Mr. Sanders by 12 percentage points to 56 percent. Still, more than seven in 10 Democratic voters expect Mrs. Clinton to win the nomination.