Republican presidential candidate Donald Trump walks out to speak in Spartanburg, S.C., after winning the South Carolina GOP primary.

Feb. 20, 2016 Republican presidential candidate Donald Trump walks out to speak in Spartanburg, S.C., after winning the South Carolina GOP primary. Jabin Botsford/The Washington Post

Donald Trump prevailed over Sen. Marco Rubio and Sen. Ted Cruz in South Carolina, sustaining his position as the Republican front-runner.

Donald Trump prevailed over Marco Rubio and Ted Cruz in South Carolina, sustaining his position as the Republican front-runner.

Donald Trump prevailed over Marco Rubio and Ted Cruz in South Carolina, sustaining his position as the Republican front-runner.

Donald Trump commandingly won the South Carolina primary on Saturday night, solidifying his position as the front-runner for the Republican presidential nomination while Sen. Marco Rubio of Florida narrowly edged Sen. Ted Cruz of Texas for second, bolstering both candidates’ status as the two leading alternatives.

The voters also delivered a devastating verdict to former Florida governor Jeb Bush, scion of a political dynasty who announced he was suspending his campaign after dismal results here. Bush came in a distant fourth — not even eclipsing 10 percent — after he and his family made an impassioned last stand in South Carolina and his allied super PAC spent millions of dollars on advertising.

“The people of Iowa and New Hampshire and South Carolina have spoken, and I really respect their decision,” Bush told a Columbia ballroom of teary-eyed and stunned supporters.

[South Carolina primary election results]

Meanwhile, in Nevada, Hillary Clinton held off a powerful challenge from Sen. Bernie Sanders in the state’s Democratic caucus vote, securing a narrow victory that helps the former secretary of state regain momentum after a crushing defeat in New Hampshire.

“Some may have doubted us, but we never doubted each other,” Clinton told supporters gathered at a Las Vegas hotel ballroom. Clinton congratulated Sanders on a close election.

[Clinton defeats Sanders in Nevada]

Bunched together about 10 points behind Trump in the South Carolina primary were Cruz and Rubio, both Cuban American first-term senators jockeying to emerge as the top rival to the billionaire mogul.

Cruz, a Texas maverick who has pitched his faith-infused candidacy as the most ideologically pure conservative, lost evangelical voters to Trump and failed overall to finish even a decisive second, revealing a potential vulnerability as the contest hurtles toward big March primaries across the South.

Rubio rebounded from his New Hampshire stumble to unite South Carolina’s new-guard Republican leaders and rally mainstream voters. He moved immediately Saturday night to fuse the party’s establishment forces behind his candidacy. “This has become a three-person race,” Rubio said, “and we will win the nomination.”

But the gulf in vote share between Rubio and Trump highlighted the possible limits of the senator’s uplifting message about generational change amid profound GOP unrest.

Trump overcame a tumultuous week in which he tangled with Pope Francis by tapping into the frustrations and economic anxieties of voters here with his red-hot rhetoric about combating terrorism and ending illegal immigration.

Former Florida governor Jeb Bush announced to supporters in South Carolina that he was suspending his presidential campaign after a disappointing performance in the state's GOP primary. (AP)

In his victory speech, Trump reveled in electoral validation for what he described as “an incredible movement with incredible people.”

“When you win, it’s beautiful, and we are going to start winning for our country because our country doesn’t win anymore,” Trump said, vowing to continue his victories from coast to coast. He congratulated Rubio and Cruz for “a really good job” but did not address Bush’s departure from the race.

Cruz asserted in his remarks to supporters Saturday night that his candidacy has put “the Washington cartel in full terror.” He said his was the only campaign that can defeat Trump.

“If you are a conservative, this is where you belong because only one strong conservative is in a position to win this race,” Cruz said.

The voters’ preferences on character traits brought the race’s emerging fault lines into sharp relief. Cruz won among voters who said their most important quality was shared values; Rubio won among those who prioritized electability; Trump won among those who most valued change or a candidate who “tells it like it is,” according to preliminary network exit poll data.

Trump’s victory signaled a striking shift for the Republican Party. In a heavily military state, Trump disavowed the party’s interventionist posture by condemning the 2003 Iraq invasion and accusing former president George W. Bush of lying about weapons of mass destruction there.

[For Cruz and Rubio, the moment has arrived: A three-man race with Trump]

Trump’s South Carolina win, coupled with his decisive victory in the New Hampshire primary, set up the celebrity businessman as the favorite heading into Tuesday’s Nevada caucuses and the 11 states holding Super Tuesday primaries or caucuses on March 1.

Since 1980, every Republican who has won both the New Hampshire and South Carolina primaries has gone on to secure the nomination.

Still, Saturday’s results indicate that the once-chaotic race could soon be reordered as a three-way contest, representing a fresh threat to Trump’s dominance in the polls with pluralities but not outright majorities.

In his concession speech, Bush hinted at the fighting still to come.

“I congratulate my competitors that are remaining on the island on their success for a race that has been hard fought, just as the contest for the presidency should be,” Bush said.

Ohio Gov. John Kasich did not replicate the magic of his second-place showing in New Hampshire and finished an anemic fifth in South Carolina. He vowed to soldier on with an optimistic message into the New England and Midwestern states coming up on the calendar.

Retired neurosurgeon Ben Carson, whose early momentum has been sapped, still nurtured enough of a grass-roots following here to round out the field in mid-single digits. He pledged to continue his campaign.

[Trump to supporters: ‘Let’s put this thing away’]

South Carolina’s electorate is representative of the Republican base, which has made the state a traditional harbinger of determining the eventual nominee. The state’s Republican voters are socially conservative, but there are deep pockets of business-friendly, establishment voters, especially in the fast-growing coastal areas.

Republicans here also have a record of rewarding pugnacity; Newt Gingrich carried South Carolina over Mitt Romney in 2012 after two electric, brawling debate performances.

Interest in the Republican primary was high and a record 735,000 people voted, roughly matching the record turnout rate set in 2000.

Roughly 8 in 10 voters considered themselves conservative, up from 68 percent who said the same in the GOP primary four years ago, and they gave substantial support to both Trump and Cruz, according to preliminary network exit poll results. Among those who said they were “very conservative,” Cruz lead Trump.

More than 7 in 10 voters considered themselves born-again or evangelical Christians, while roughly three-quarters of the primary electorate said they wanted a candidate who shares their religious beliefs, a significant increase from 2012, the data show.

In the Iowa caucuses, Cruz’s victory was fueled by a double-

digit edge among evangelicals over Trump, but in South Carolina the two candidates had roughly the same share, according to the exit polls.

Asked which qualities were important, 37 percent of voters said they were seeking a candidate who shares their values, while

31 percent said they were looking for someone to bring change, according to the poll data.

The vast majority of Republican primary voters said they were at least dissatisfied with the federal government, the data show, and Trump won among those who said they were “angry.”

As in the earlier contests, Trump performed better here with men than with women. In an apparent effort to soften his image, he yielded the lectern during his victory speech to his wife, Melania, and then his elder daughter, Ivanka, who both gave glowing testimonials.

[Nearly $100 million in super PAC money couldn’t save Jeb Bush]

For Bush, in contrast, South Carolina represented a swan song. Following a fourth-place finish in New Hampshire, which gave him hope of a comeback, Bush failed to generate widespread enthusiasm here in spite of efforts to revive Bush family nostalgia with high-profile visits by his former-president brother, as well as his mother, former first lady Barbara Bush. While the former president’s rally drew an enthusiastic crowd, Jeb Bush’s other events were far more muted.

Bush’s uneasy presentations at town halls in the final days of the primary race reflected the anxiety within his orbit about the future of his candidacy.

A crippling moment came Wednesday when South Carolina’s popular governor, Nikki Haley, endorsed Bush’s one-time Florida protege, Rubio. She then barnstormed the state with Rubio as well as Sen. Tim Scott and Rep. Trey Gowdy for three days.

Sounding a triumphant note in his Saturday night speech to supporters, Rubio said: “Ronald Reagan made us believe that it was ‘morning in America’ again — and it was. Now, the children of the Reagan Revolution are ready to assume the mantle of leadership.”

Scott Clement in Washington and Abby Phillip, John Wagner and Anne Gearan in Las Vegas contributed to this report.