South Carolina Gov. Henry McMaster is hoping that the full-fledged support of the Trump administration will be enough to sway voters in the Palmetto State to go to the polls for him in his runoff against businessman John Warren.

McMaster -- who ascended to his post after Trump picked his predecessor, Nikki Haley, to be the United States ambassador to the United Nations – saw the majority of South Carolina Republicans vote against him in this month’s gubernatorial primary, while Warren has won the support from the third- and fourth-place finishers in the race and Republican Rep. Ralph Norman.

But The White House is throwing everything at its disposal into the race to save McMaster, who went out on a political limb for Trump at a crucial point in the 2016 Republican presidential primaries.

Trump issued several tweets over the past week praising the governor and noting his loyalty. He dispatched Vice President Pence to the state on Saturday and will himself stump for McMaster on Monday afternoon in West Columbia.

When voters in South Carolina return to the polls Tuesday, they'll be deciding in part which is more meaningful: a Trump endorsement, or a candidate who embodies some of Trump's outsider credentials.

"I think that if anyone supported Donald Trump and they look and truly give an honest assessment of whose resume and whose background is more similar to Donald Trump, they will side with me," Warren told The Associated Press in a recent interview. "It is clear I'm an outsider. I am a businessman. I'm a conservative. The establishment doesn't want me to get elected."

With all the attention coming from the White House, Winthrop University political scientist Scott Huffmon said it's impossible for voters to ignore the factor that the president could play in the race.

"Trump's obviously floating around over all of this. You have one candidate endorsed by Trump, but he's the consummate insider. But then you have a Trump-like candidate," Huffmon said. "When you have Trump's endorsement, but you're running against someone who is very Trump-like, you've got to switch gears and figure out the way you can undermine them."

The president’s support, however, does not guarantee that McMaster will win on Tuesday.

In Alabama's GOP Senate primary last year, the president originally supported Sen. Luther Strange, who lost the nod to Roy Moore. Trump then stuck with Moore in the general election, even after he was hit with multiple allegations of sexual misconduct. Moore lost the race to Democrat Doug Jones. In a Pennsylvania district Trump carried in 2016 by 20 points, Republican Rick Saccone won Trump's endorsement, but lost to Democrat Conor Lamb by a razor-thin margin.

But Trump is exuding confidence following his successful endorsement this month of state Rep. Katie Arrington in a race against Sanford. The president took another victory lap last week, calling Sanford a "nasty guy" in a closed-door GOP conference meeting.

South Carolina went solidly for Trump in 2016 and remains solid Republican territory. The winner on Tuesday will face Democrat James Smith in the general election.

The Associated Press contributed to this report.