Sen. Rand PaulRandal (Rand) Howard PaulDem wins Kentucky state House seat in district Trump won by 49 points GOP's tax reform bait-and-switch will widen inequality Pentagon budget euphoria could be short-lived 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.