2016 hopefuls heading to South Carolina for Haley rally

Sen. Rand PaulRand PaulSaudi skeptics gain strength in Congress Senators challenge status quo on Saudi arms sales Five tips from Trump's fallen rivals on how to debate him 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.