Donald Trump holds a 19-point lead over Ted Cruz among those likely to vote in Saturday's South Carolina Republican primary, with Marco Rubio and Jeb Bush locked in a close race for third and John Kasich showing no signs of a surge.

A Bloomberg Politics poll shows the billionaire dominating the field across virtually all demographic groups, and doing even better than Cruz among those who say they are either very conservative or evangelical Christian. On nearly every question about challenges faced by the next president, Trump scores the highest.

The real estate mogul is gathering broad support in the first state to vote in the manners-conscious South despite striking discordant notes with a majority of likely voters, who agree that he's used language that's crass, un-presidential, and reflecting bad manners and taste.

“From the size of the lead and the nearness of voting day, it is easy to say this is Trump’s election to lose,” said pollster J. Ann Selzer, who oversaw the survey. “While his linguistic choices turn off a majority of voters, he speaks for the people who want radical change in Washington. South Carolina may just be ready to forgive bad manners in exchange for what they see as a strong leader.”

Read the questions and methodology here.

Trump leads the field with support from 36 percent of likely voters, followed by Cruz, the junior senator from Texas, at 17 percent. Rubio, the junior senator from Florida, is at 15 percent, closely followed by Bush, a former Florida governor, at 13 percent. Stuck at the bottom are retired neurosurgeon Ben Carson at 9 percent and Kasich, the Ohio governor, at 7 percent.

Rubio could get a boost from the endorsement of South Carolina Governor Nikki Haley, who has been critical of Trump's hardline immigration rhetoric. She's viewed positively by 68 percent of those surveyed, the highest of any Republican politician tested in the poll. Trump did not appear to be hurt by a highly combative South Carolina debate performance Saturday, with his level of support staying between 30 percent and 40 percent on each of four nights of polling, with highest scores coming on Sunday and Tuesday nights.

In keeping with the state’s tradition of not deciding on a candidate until the final days of a campaign, 43 percent of South Carolina primary voters say either they haven't made up their minds or they could be persuaded to support someone other than their first choice. But supporters of Trump (63 percent) and Cruz (68 percent) have already locked their choice in larger proportions than the average for candidates in the race (56 percent).

Following the death of Justice Antonin Scalia, likely primary voters were asked about the best approach to fill the Supreme Court vacancy. Fifty-four percent said the Republican-controlled U.S. Senate shouldn't hold hearings on any nominee, while 42 percent wanted hearings and votes on anyone put forward by President Barack Obama. Women are more likely than men to oppose hearings, 61 percent to 46 percent.

QuickTake How the U.S. Elects Its Presidents

Among self-described mainstream Republicans—the largest share of the electorate—Trump has the most support at 38 percent, followed by Bush at 20 percent, Rubio at 14 percent, Kasich at 12 percent and Cruz at 11 percent.

Trump leads among men (38 percent to 15 percent) and women (33 percent to 18 percent), as well as those who have less than a college degree (46 percent to 14 percent) and those who do have one (28 percent to 18 percent).

Trump scores the highest on nearly all questions seeking to gauge presidential qualities. Respondents say he is the candidate who would be most feared by America’s enemies (57 percent); take on the Washington establishment (51 percent); win November's general election (43 percent); bring about needed change (43 percent); have the right approach to illegal immigration (41 percent); be the strongest leader (41 percent); keep families safe (39 percent); and appoint the best Supreme Court justices (24 percent).

Trump also holds a big lead among those who say the system is rigged, 48 percent to 15 percent over Cruz. And the front-runner’s tough talk on trade may be helping him with likely primary voters, with 50 percent saying that trade agreements like the proposed Trans-Pacific Partnership hurt job prospects in their state, while only 20 percent say it helps.

More than a third of those surveyed, however, would be “not OK” with him becoming the nominee, the highest among the candidates and an indication of how polarizing he is even among Republicans. More than a third of poll participants said Trump isn't religious enough to be a good president, while 47 percent say he'd be “too radical” to lead the nation.

A plurality of the likely primary voters—39 percent—view themselves primarily as “mainstream Republicans,” while a third identify as “religious conservatives” and 20 percent as Tea Party. About a fifth of those likely to cast ballots Saturday say they'll be doing so for the first time in a primary.

The survey, conducted Feb. 13-16 by Selzer & Co. of West Des Moines, Iowa, included 502 likely Republican primary voters. It has a margin of error of plus or minus 4.4 percentage points.

The survey contained some discouraging signs for Rubio, with more than a third of poll participants viewing the 44-year-old senator as too young to be a good president, and only 16 percent say he could win the general election in November despite his focus on electability as a key selling point to voters.

The Florida senator’s stumble in a debate just before the New Hampshire primary, where he repeatedly used the same line, left South Carolina primary voters split—45 percent to 46 percent—on whether his actions mean he can stay on message, or doesn't think well on his feet and robotically repeats the same lines.

Cruz’s lack of endorsements by fellow U.S. senators is viewed as a negative by 47 percent, with that share agreeing he “doesn't have the necessary relationships to bring about change because people do not want to work with him.” Forty-two percent see his lack of endorsements as a reflection of a willingness to take on powerful interests, even in his party.

For Bush, the state’s likely voters appeared split on his family ties. Forty-nine percent say that he's riding on family coattails with experience rooted in the past, compared to 41 percent who say being the son and brother of past presidents makes him “supremely qualified” for the job.

Despite trailing in fifth place, Carson has the highest favorability rating among the candidates, at 65 percent, followed by Rubio at 64 percent, Trump at 55 percent, Cruz at 54 percent, Bush at 51 percent and Kasich at 41 percent.

Between the state's two U.S. senators, Lindsey Graham and Tim Scott, it seems the junior senator might be a more useful endorsement among likely primary voters. Scott, who is backing Rubio, is viewed favorably by 61 percent, with only 13 percent having unfavorable views. Graham, who is backing Bush, is viewed favorably by 41 percent and unfavorably by 51 percent.

No matter how their preferred candidate does, a majority of likely Republican primary voters said they want the candidates to be realistic, if it looks like they don't have a chance to win the nomination.

A solid majority—60 percent— said it would be better for a candidate to sacrifice his campaign, support a competitor and help unify the party for the general election, compared to 32 percent who said it would be better for their candidate to keeping fighting.

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