"It's obviously going to make the race very fractious, very interesting with the potential to have a lot of unflattering portraits," a pollster told Newsweek.

Republican Rep. Nancy Mace of South Carolina is running for governor, entering a GOP primary in which competition for President Donald Trump's endorsement — and the backing of his base of supporters — is expected to be fierce.

She joins a crowded Republican primary field that includes a rival candidate she has already clashed with sharply this year.