Clinton wins Nevada caucuses

  COLUMBIA, S.C. (AP) -- Hillary Clinton pulled out a crucial victory in Nevada's Democratic caucuses Saturday, overcoming an unexpectedly strong surge by Bernie Sanders and potentially easing the anxiety of some of her supporters.
   "To everyone who turned out in every corner of Nevada with determination and heart: This is your win," Clinton said on Twitter.
   Clinton captured the backing of voters who said electability and experience were important in their vote. But in a continuing sign of her vulnerability, Sanders did best with voters looking for a candidate who is caring and honest.
   Sanders said in a statement that he'd congratulated Clinton on her victory, but then declared his campaign has "the wind at our backs as we head toward Super Tuesday" -- the multi-state voting contests on March 1.
   Nevada was the first of two presidential primary contests being held Saturday. Republicans were battling in South Carolina, a state seen as billionaire Donald Trump's to lose and one that could start to clarify who, if any, of the more mainstream candidates might emerge to challenge him.
   But the South Carolina electorate had warnings for more traditional GOP politicians. Half of voters said they felt betrayed by politicians in the Republican Party.
   For both parties, the 2016 election has laid bare voters' frustration with Washington and the influence of big money in the political system. The public mood has upended the usual political order, giving Sanders and Trump openings while leaving more traditional candidates scrambling to find their footing.
   Clinton's victory in Nevada could be vital in holding off a challenge from Sanders that has been tougher than almost anyone expected. Clinton and Sanders split the first two voting contests, revealing the Vermont senator's appeal with young people drawn to his impassioned calls for breaking up Wall Street banks and providing free tuition at public colleges and universities.
   According to the entrance polls of voters, Clinton was backed by a majority of women, college-educated voters, those with annual incomes over $100,000, moderates, voters aged 45 and older and non-white voters. Sanders did best with men, voters under 45 and those less affluent and educated.
   Clinton's win means she will pick up at least 18 of Nevada's 35 delegates. She already holds a sizeable lead in the delegate count based largely on her support from superdelegates -- the party leaders who can support the candidate of their choice, no matter the outcome of primaries and caucuses.
   Republicans were voting in South Carolina, the first Southern state in the 2016 presidential election. Trump spent the week threatening one rival with a lawsuit, accusing former President George W. Bush of lying, and even tangling with Pope Francis on immigration, yet he still entered the primary contest in strong position.
   The prospect of a Trump win alarmed rival Jeb Bush, the former Florida governor trying mightily for a strong showing in the first Southern state to vote.
   "Trump can't win, plain and simple," Bush told reporters outside a polling place in Greenville. "A ton of people would be very uncomfortable with his divisive language and with his inexperience in so many ways."
   A Trump victory could foreshadow a solid performance in the collection of Southern states that vote on March 1. Victories in those Super Tuesday contests could put the billionaire in a commanding position in the delegate count, which determines the nomination.
   Texas Sen. Ted Cruz banked on a well-regarded get-out-the-vote operation and 10,000 volunteers to help overtake Trump on Saturday, as well as in the Southern states that follow.
   A failure to top Trump in South Carolina could puncture that strategy, though Cruz, who sidetracked briefly to Washington to attend the late Supreme Court Justice Antonin Scalia's funeral Mass, will still have more than enough money to run a long campaign.
   Marco Rubio and Bush were fighting to establish themselves as credible alternatives to Trump and Cruz, candidates some GOP leaders believe are unelectable in November.
   Neither Bush nor Rubio expected to win South Carolina. But they wanted to finish ahead of one another; otherwise, there would be tough questions about long-term viability.
   Rubio scored the endorsements of several prominent South Carolina politicians, including Gov. Nikki Haley, and seemed to have rebounded after a dismal debate performance two weeks ago. Bush hoped his deep family ties to South Carolina -- his brother and father each won two primaries here -- would be a lifeline for his struggling campaign.
   Also in the mix was Ohio Gov. John Kasich, who had low expectations in South Carolina. He was looking toward more moderate states that vote later in March. Retired neurosurgeon Ben Carson had a small but loyal cadre of followers.
   Democrats and Republicans will swap locations in the coming days. The GOP holds its caucus in Nevada on Tuesday, while Democrats face off in South Carolina on Feb. 27.
   The polling of voters in Nevada and South Carolina was conducted for The Associated Press and the television networks by Edison Research as voters arrived at 25 randomly selected caucus sites.
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   Pace reported from Washington. Associated Press writers Ken Thomas in Las Vegas and Alex Sanz in Greenville, and AP News Survey Specialist Emily Swan contributed to this report.