The Associated Press and other US media outlets swiftly declared Trump the winner of the state’s GOP primary shortly after the polls closed on Saturday evening.

The final results have not yet been released, but Trump was leading 59.7 percent to 39.7 percent with about half of the expected vote counted, according to Edison Research.

Speaking to supporters at an election night party in the state capital of Columbia, the ex-president turned his attention to November’s general election and promised that if he is re-elected, the US would be “respected like never before”.

“There’s never been a spirit like this,” Trump said. “I have never seen the Republican Party so unified as it is right now.”

The former president has maintained a strong grip over the Republican caucus despite facing a slew of civil and criminal cases against him, sweeping every state contest so far.

Trump’s victory in South Carolina also makes it increasingly likely that he will face a rematch against his Democratic rival, President Joe Biden, in November.

Al Jazeera’s Shihab Rattansi, reporting from South Carolina on Saturday, noted that Trump did not even mention Haley’s name during his victory speech.

“That is going to be the policy going forward,” Rattansi said. “This is all about Biden.”

But Haley, who served as South Carolina’s governor from 2011 to 2017, has pledged to continue her campaign at least through the Super Tuesday contests on March 5. That’s the day 15 US states and a territory hold their primaries.

“I said earlier this week that, no matter what happens in South Carolina, I would continue to run for president,” Haley said in a speech to supporters in the city of Charleston after her loss. “I’m a woman of my word.”

Her commitment to continuing drew chants of “Nikki! Nikki!” from the crowd.

“I’m not giving up this fight when a majority of Americans disapprove of both Donald Trump and Joe Biden,” Haley added.

“South Carolina has spoken; we’re the fourth state to do so. In the next 10 days, another 21 states and territories will speak. They have the right to a real choice, not a Soviet-style election with only one candidate. And I have a duty to give them that choice.”

Haley said she plans to head to Michigan on Sunday, just days ahead of that state’s Republican primary on February 27. Then, her campaign will turn its attention to Super Tuesday states, which include Minnesota, Vermont and Colorado.

But the former UN ambassador has no real path to winning the Republican Party nomination – and the party has largely hitched its wagon to Trump.

Even in her home state, Haley struggled to rally high-profile political endorsements. Only one Republican representative from South Carolina, Ralph Norman, backed her over Trump.

Trump, meanwhile, celebrated his South Carolina victory with a row of his backers, including both of South Carolina’s senators – Tim Scott and Lindsey Graham – as well as the state’s governor.

He had arrived in South Carolina shortly after delivering a speech at the Conservative Political Action Conference (CPAC) in Maryland, the largest annual gathering for conservatives in the country.

Many of his remarks there were focused on Biden. In his 90-minute speech, Trump accused the president of overseeing the country’s decline.

He added that, if he beats Biden in November, it will represent a “judgement day” for the US and his “ultimate and absolute revenge”.

For his part, Biden has warned that the former Republican president likewise poses a threat to the country.

Last month, Biden characterised Trump and his followers as dangerous outliers. The Democratic president asked his party, independents and “mainstream Republicans” who cherish US democracy to back him.

“Democracy is on the ballot. Your freedom is on the ballot,” Biden said.

Trump faces four separate criminal indictments, including two related to his efforts to overturn the results of the 2020 presidential election – a contest he lost to Biden.

His first criminal trial – on charges of falsifying business documents in connection to hush-money payments – is scheduled to begin on March 25 in New York City.

Trump has denied wrongdoing in all the cases and said they are part of a politically motivated witch hunt.