Updated

Mitt Romney rode overwhelming backing from Mormons and his best performance yet among conservatives to his emphatic victory Saturday in Nevada's Republican presidential contest, according to preliminary results of a poll of voters entering the caucuses.

Buoyed by near monolithic support from Mormons, the former Massachusetts governor won a broad and deep victory. He was the clear winner among every age group except for those under 30, with all but the lowest-earning voters and across all levels of education.

"We were just talking on our way over here about how great it is to be excited about the political process again," said Leanne Fertig, a 58-year-old Clark County school district employee. "It's due to Mitt Romney. We have a candidate we can believe in."

Romney captured the votes of just over half of conservatives, more than doubling the number who backed former House Speaker Newt Gingrich, an ominous result for the man who has emerged as Romney's chief rival.

In the four previous states that have held GOP presidential contests, Romney had won no more than about 4 in 10 conservative votes, in New Hampshire and Florida. Underscoring the importance of the Mormon vote, Romney's support Saturday among conservatives who are not Mormon was in that same 4 in 10 range.

For the first time, Romney took half the votes of tea party supporters, with Mormons once again pushing his margin higher than before.

One in 4 voters Saturday was Mormon, Romney's religion, and 9 in 10 of them backed him. They provided him with more than 4 in 10 of his votes on Saturday. Each of his rivals received 1 in 10 or less of their votes from Mormons.

Romney won among all non-Mormon voters as well, though by a narrower margin, capturing around 4 in 10 of their votes. Romney won among born-again and evangelical Christians -- a group he has usually struggled with -- prevailed among Protestants and carried a slight majority of Catholics.

Gingrich and Texas Rep. Ron Paul each took about 1 in 4 of Saturday's non-Mormon voters.

Romney won decisively among the nearly half of voters saying they most wanted a candidate who can defeat President Barack Obama in this fall's election. He won about three quarters of their votes -- four times as many as went to Gingrich, his nearest competitor on that question.

Romney also won among people seeking a contender with the right experience and with strong moral character.

Yet on the moral character question, his backing from Mormons was key. Among non-Mormons seeking that quality, Paul was the big winner.

Just over half said the economy was their chief issue as they decided which contender to back, and 6 in 10 of them picked Romney, who has trumpeted his business background at a time when the nation's job market has limped slowly in the right direction. He also won among the 1 in 3 who named the federal deficit as their top concern.

The evening seemed like a disappointing one for Paul, who spent nearly as much as Romney in Nevada on campaign advertising and had hoped to prosper in a state that is home to many with libertarian views.

Paul triumphed among only a handful of groups of voters. He won among the 1 in 5 independents, among the 1 in 5 who said they were seeking a candidate who was a true conservative and with the small number who said they are not members of a religion. He shared the lead with people under age 30 and with those earning less than $30,000 annually.

The survey was conducted for AP and the television networks by Edison Research as voters arrived at 25 randomly selected caucus sites in Nevada. The survey involved interviews with 1,584 caucus-goers and had a margin of sampling error of plus or minus 4 percentage points.