Sen. Rand PaulRandal (Rand) Howard PaulKentucky Dems look to vault themselves in deep-red district Overnight Defense: Senate confirms Haspel as CIA chief | Trump offers Kim 'protections' if he gives up nukes | Dem amendments target Trump military parade Hillicon Valley: Lawmakers target Chinese tech giants | Dems move to save top cyber post | Trump gets a new CIA chief | Ryan delays election security briefing | Twitter CEO meets lawmakers MORE (R-S.C.) will also be in the state to fundraise for Rep. Jeff Duncan (R-S.C.).

It's unclear how much help Haley could be in a presidential primary, however. She's faced less-than-stellar approval ratings within the GOP and her endorsement of Mitt Romney in 2012 did little to help his campaign there.

Haley is facing what looks to be a tough challenge from South Carolina state Sen. Vince Sheheen (D), who ran a close race against her in 2010.