Immigration the key issue as Trump trounces Nikki Haley but critics claim party is divided because former South Carolina governor got 40 percent in her home state

Donald Trump's resounding victory over Nikki Haley in her home state of South Carolina on Saturday came as immigration was overwhelmingly the most important issue for voters.

The former president trounced Haley by 60 points to 40 in the Republican primary in a humiliating defeat.

Exit polls showed immigration was the most important issue for 41 percent of voters, well ahead of the economy on 31 percent.

Trump has based much of his campaigning on his pledge to tighten up defense of the border against illegal immigration.

Haley, the former UN Ambassador, has based much of her campaigning on her foreign policy experience.

But only 11 percent said that was the most important issue, according to a CNN poll.

MSNBC's Lawrence O'Donnell warned that the numbers behind Trump's triumph in South Carolina do not give him a path to the White House 

The former president did not mention Nikki Haley by name in his South Carolina victory speech as he cast his eyes forward to November's general election 

Haley, insisted she would remain in the race with more than 700 delegates up for grabs on Super Tuesday' March 5 when 15 states and one territory will cast their votes

Trump has swept all the contests so far, winning Iowa, New Hampshire, and Nevada, and could be crowned as early as March 12 if results continue to go his way.

However, one in five Republican primary voters now say they will not vote for him in November, according to surveys.

That would be enough to hand the race to Joe Biden who won Saturday's Democrat primary hands down.

'These numbers are disastrous for Donald Trump,' claimed Lawrence O'Donnell on MSNBC as the results came in. 

'It's the reason I mentioned the big forgotten number of South Carolina, which is Joe Biden getting 96%, okay?

'That's what you're supposed to get, alright, and Donald Trump's not going to come close to that.'

'He's going to leave that on the table, belonging to another candidate. All you need, all you need, is 5% of the 30%. We're talking about a sliver.'

The former president said he had 'never seen the Republican Party so unified as it is right now', as he held a victory rally in a Colombia hotel ballroom on Saturday night.

'I just wish we could do it quicker.'

It has been more than 50 years since a Republican presidential candidate has clinched the GOP nomination without winning their home state.

But Haley insisted she was in for the long haul, telling her supporters: 'I know 40% is not 50% but I also know 40% is not some tiny group.

'There are huge numbers of voters in our Republican primaries who are saying they want an alternative.'

Sixty percent of voters in the South Carolina primary voters identify as white evangelical or born-again Christians and Trump won three-quarters of their votes.

The average age of voters was older than in any previous election in the state and three-quarters of those without a college degree voted for Trump.

But a Bloomberg poll at the end of last month found that a majority of voters in key swing states would not vote for the ex-president if he were to be convicted in any of the 90 felony counts he is facing over his last period in office.

O'Donnell's fellow panelists agreed the figures looked bad as the results came in with Rachel Maddow calling it 'not a good look', and Stephanie Ruhle declaring Biden the 'winner of the night'.

But the liberal media has a long history of underestimating the width of Trump's support and his campaign warned it risked the same sort of complacency it showed before Hillary Clinton lost to him in 2016.

'This is going to be a referendum against Joe Biden and his policies,' a Trump adviser told Mediaite.

'As long as Trump can tap into voter disillusion about the economy, out-of-control immigration, and more foreign entanglements, those are issues that affect people from all backgrounds.'

Trump now has 110 delegates to take to the Republican National Convention in Milwaukee on July 15 when the winner is formally declared.

The liberal panel on MSNBC's election night coverage agreed with O'Donnell's analysis 

His only remaining rival has 20 of the 1,215 needed to secure the nomination but more than 700 are up for grabs on 'Super Tuesday' March 5 when 15 states and one territory will cast their votes.

Trump however is already looking forward to November when he insists he will win back the White House he lost in 2020.

'For hardworking Americans, November 5 will be our new Liberation Day,' he said in a speech to the conservative CPAC conference yesterday.

'But for the liars and cheaters and fraudsters and censors and imposters who have commandeered our government, it will be Judgment Day.'