Trump under pressure to show more presidential side at debate

With a week to go until South Carolina's Republican primary vote on February 20, the 9 pm EST debate comes at a time of high anxiety for Trump's opponents.

The death of Supreme Court Justice Antonin Scalia, a champion of conservatives, was likely to be a prime topic at the debate. The prevailing opinion among the Republican candidates was that Scalia's replacement should be left up to the next president and not Democratic President Barack Obama, who could change the conservatives' 5-4 advantage on the court.

Trump, who won New Hampshire handily on Tuesday after placing second in Iowa on February 1, has a big lead in the polls in South Carolina. Unless he is slowed down, he could be in position to roll to his party's presidential nomination for the November 8 election.

That means it is in the interests of Texas Senator Ted Cruz, Florida Senator Marco Rubio and former Florida Governor Jeb Bush to try to raise questions about the New York billionaire before it is too late.

Those three candidates, along with Ohio Governor John Kasich, are competing to emerge as the top alternative to Trump for mainstream Republicans.

"My sense is this is going to be a melee," said Republican strategist Doug Heye.

Attempts to knock down Trump at previous debates have rarely been successful, as the former reality TV star has been quick on his feet and mercilessly dismissive of rivals.

Trump's use of vulgar language during the New Hampshire primary campaign, repeating a comment from someone at one of his rallies who said Cruz is a "pussy," may raise eyebrows in South Carolina, where evangelicals form an important voting bloc.

At a candidates' forum at evangelical Bob Jones University on Friday, Bush told the crowd: "Is anybody worried about the front-running candidate shouting out obscenities at children?"

Trump was not at the event, sending instead a surrogate to speak for him, Pastor Mark Burns. When Burns told the crowd that Trump is "pro-faith," someone shouted out from the audience "Trump is profane."

'EACH HAS SOME IMAGE ISSUE'

All Trump's rivals have something to prove at the CBS-hosted, two-hour debate, particularly Rubio, who needs to show he can rebound from a disastrous debate performance a week ago in New Hampshire.

Kasich must try to generate more momentum after a second-place finish in New Hampshire, Cruz must solidify his position with evangelical voters and Bush needs upward movement anywhere he can get it.

Retired neurosurgeon Ben Carson, whose campaign has turned anemic, has to show he is still in the race.

"Each has got some image issue they need to fix," said David Yepsen, director of the Paul Simon Public Policy Institute at Southern Illinois University.

"Can Trump start acting more presidential without losing what makes him so appealing? Can Jeb continue the flicker of momentum he has coming out of New Hampshire? Have Rubio's bruises healed? Can Carson show something that puts a spark back into his campaign? Has Kasich got more than his New Hampshire game?"

Heading into the debate, Trump was taking swipes at Cruz and Bush, who finished third and fourth in the New Hampshire primary.

Responding to an attack ad run by the Cruz campaign against him, Trump tweeted that he might sue Cruz to try to settle any remaining questions about whether the Texan can legally run for president since he was born in Canada.

Cruz and many legal experts say Cruz meets the constitutional requirements because he was born to an American mother and grew up in the United States. But Trump, who famously questioned President Obama's citizenship, fired off a tweet against Cruz.

"If @TedCruz doesn't clean up his act, stop cheating, & doing negative ads, I have standing to sue him for not being a natural born citizen," Trump said.

The Cruz campaign dismissed the blast with spokesman Rick Tyler saying Trump was demonstrating a "Trumper-tantrum."