WATCH: Mace says Trump's endorsement hasn't sealed SC gubernatorial race: ‘It’s a dog fight’

Rep. Nancy Mace, R-S.C., told Fox News Digital ahead of Tuesday's South Carolina Republican gubernatorial primary that President Donald Trump's endorsement has done little to boost her opponent's standing with conservative voters, arguing that many grassroots Republicans are "very upset" with the decision.

"It's not going over well for her with the grassroots, which is why she didn't get much of a bump," Mace said. "She got maybe a five point bump — not much."

"And she's going to be...