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

"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 says she plans to start a statewide series of town halls this week in Myrtle Beach now that she's running for governor.