Most, however -- 59 percent -- said it would have no effect on their vote.

The telephone poll of 400 Nevada voters was conducted Aug. 13-15 by Washington, D.C.-based Mason-Dixon Polling & Research Inc.

The result confirms what many Nevada political watchers have suspected. Romney, a former Massachusetts governor and member of the Church of Jesus Christ of Latter-day Saints, overwhelmingly won Nevada's Jan. 19 Republican caucuses, running away with 51 percent of the vote.

Renegade Texas Rep. Ron Paul came in second, while McCain was third with 13 percent of the vote.

Romney was the only GOP candidate who built a significant campaign organization in Nevada for the caucuses, which were overshadowed by a same-day South Carolina primary.

Exit polls found that Mormons made up about 25 percent of Nevada Republican caucus-goers, and more than 90 percent of them supported Romney.

In the poll, two-thirds of LDS voters said they'd be more likely to vote for McCain with Romney by his side. None said they would be less likely, and 33 percent said Romney wouldn't affect their choice.

Mason-Dixon Managing Partner Brad Coker estimated the Mormon vote at about 9 percent in Nevada and said in a state expected to be close on Nov. 4, Romney could put McCain over the top.

"It certainly looks like having him on the ticket would help a little bit in Nevada," Coker said, adding that turnout among LDS voters might be higher for a Romney ticket.

"In a state that in the end is probably a one- or two-point state, those extra votes could be beneficial," he said. "Everybody talks about Romney helping McCain in Michigan and shoring him up on the economy. But Nevada might be the battleground state where Romney would really be a plus."

Contact reporter Molly Ball at mball @reviewjournal.com or 702-387-2919.