( AP )- Mitt Romney won quiet Republican presidential caucuses in Nevada on Saturday while John McCain and Mike Huckabee dueled in a hard-fought South Carolina primary, a campaign doubleheader likely to winnow the crowded field of White House rivals.
Democrats shared the stage in Nevada, where Hillary Rodham Clinton and Barack Obama vied for a caucus victory and the campaign momentum that goes with it.
Romney's western victory marked his second straight success, coming quickly after a first-place finish in the Michigan primary revived a faltering campaign.
Nevada Republicans said the economy and illegal immigration were their top concerns, according to preliminary results from surveys of voters entering their caucuses. Romney, the former Massachusetts governor, was leader among voters who cited both issues.
Mormons comprised about 20 percent of all caucus-goers, another advantage for Romney, who is trying to become the first member of the faith to win the White House.
Alone among the Republican contenders, Rep. Ron Paul of Texas aired television ads in Nevada, and the libertarian-leaning Texan was running a distant second behind Romney.
The first scattered returns showed Romney with about 46 percent of the vote. Paul and McCain were close together, far behind in second place.
Nevada offered more delegates but far less appeal to the Republican candidates than South Carolina, a primary that has gone to the party's eventual nominee every four years since 1980.
That made it a magnet for former Tennessee Sen. Fred Thompson, who staked his candidacy on a strong showing, as well as for Romney, McCain, the Arizona senator; and Huckabee , the former governor of Arkansas.
McCain, a former Vietnam prisoner of war, appealed to a large population of military veterans in South Carolina, and stressed his determination to rein in federal spending as he worked to avenge a bitter defeat in the 2000 primary.
Huckabee reached out to evangelical Christian voters, hoping to rebound from a string of disappointing showings since his victory in the Jan. 3 Iowa caucuses.
Romney campaigned on a pledge to help restore the state's economy, much as he did in winning Michigan.
In South Carolina, the economy and immigration were cited as top issues, and preliminary survey data indicated a strong turnout by evangelical voters.
Survey data in both states were from polls conducted for The Associated Press and the television networks by Edison Media Research and Mitofsky International.
Alone among the major Republican contenders, former New York Mayor Rudy Giuliani skipped the day's events. He camped out in Florida, the first of the big states to vote, with a winner-take-all primary on Jan. 29.
If the Republican race had no clear front-runner, the Democrats had two, and little room in the campaign spotlight for the third man on the ballot, former Sen. John Edwards.
Obama and Clinton both ran all-out in Nevada, even though only 25 delegates are at stake.
Obama won the backing of an influential Culinary Workers Union. That, in turn, led to an unsuccessful lawsuit by some of Clinton's supporters who hoped to ban specially arranged caucuses along the Las Vegas Strip that could draw thousands of unionized casino and hotel workers.
Obama , hoping to become the first black president, spent nearly $1 million in television commercials. Clinton, campaigning to become the country's first woman chief executive, ran nearly $700,000 worth of commercials, and a union group backed her with nearly $100,000 spent on an independent ad campaign.
Former President Clinton was a constant presence, as well, in a state he carried twice on his own in 1992 and 1996.
Remarkably, neither Obama nor Clinton has aired a television commercial criticizing the other, and both of the rivals stepped back earlier in the week from a controversy over race. But that didn't prevent almost constant sniping between the two camps, each pointing out alleged inconsistencies in the other's record.
Huckabee , greeting voters at a polling place in South Carolina, said he was worried about turnout in the more conservative upstate regions.
"You never know how that's going to affect people who will go your way or the other way," he told reporters. "And obviously, the upstate is an important part of South Carolina for us, and if it starts snowing up there, that's something we hope doesn't happen. But we have to take the weather what it is. We don't get to choose.
"I just hope that our voters are so committed that it doesn't affect the fact that they're going to go out and vote, because they believe this is a mission," Huckabee said.
McCain got in some last-minute campaigning at a plant that makes armored vehicles for troops in Iraq and Afghanistan, then said he and his wife Cindy would take in a movie.
His choice: "There will be Blood," a historical epic set in California's oil boom region a century ago.
In southern areas of the state, a misty rain greeted people at the polls.
Doug Pinkerton, a financial adviser, was among about 20 people who voted early in Mount Pleasant.
"Giuliani was my original favorite, but he seems to be running such a halfhearted campaign and putting it all on Florida. I just think that was a bad idea. If he had campaigned here more and showed some interest I probably would have voted for him, but I think that Romney will be the candidate," said Pinkerton, 59.
David Dawson, an information technology manager, said he cast his vote for McCain because he believed the Arizona senator is the most honest. "I rely on him to tell us the truth whether we like it or not. That is pretty much it," said Dawson, 32.