In 2010 Nikki Haley was elected Governor of South Carolina by a 51/47 margin, an uninspiring performance given the red hue of the state and what a strong year it was for Republicans nationally. Since then Haley has proven to be an unpopular Governor, and the national political climate has gotten far better for Democrats. As a result Haley now trails her 2010 Democratic opponent, Vincent Sheheen, 46/44 in a hypothetical rematch.
Sheheen is able to overcome South Carolina's GOP lean for two key reasons. He has a 51/35 advantage over Haley with independents, and he's picking up 15% of the Republican vote while losing only 10% of Democrats. Sheheen leads Haley despite having relatively low name recognition- only 45% of voters are familiar enough with him to have an opinion, suggesting some of the profile he built up in 2010 has already receded.
The good news for Haley in this poll is that she does not look terribly vulnerable to a primary challenger. In general 53% of Republicans want her to be the nominee again in 2014 to 37% who would prefer someone else. When pitted against a couple specific potential foes she's ahead by even wider margins- 58/26 against Lieutenant Governor Glenn McConnell and 66/18 against Treasurer Curtis Loftis.
Lindsey Graham has really improved his standing with Republican primary voters over the last year. In January of 2011 we found that only 37% of GOP voters would support him in a primary, compared to 52% who preferred a more conservative alternative to Graham. Since then Graham has improved a net 26 points on that measure and now leads a generic 'more conservative' foe 51/40. Graham's approval rating with Republican primary voters is a relatively healthy 66/26 spread.
When pitted against actual potential primary opponents Graham, like Haley, does even better than he does versus generic ones. He leads Tim Scott 54-32, Trey Gowdy 57-29, Mark Sanford 64-26, Mick Mulvaney 64-20, and Tom Davis 67-17.