Sen. Lindsey Graham (R-S.C.), who is being targeted from the right in his 2014 primary, has lost a huge amount of support from Republicans in recent months, according to a new poll.

The Winthrop University poll shows Graham's approval rating among GOPers has dropped from 72 percent in February to 45 percent today.

Four in 10 Republicans (40 percent) disapprove of Graham.

Graham faces several primary challengers, including state Sen. Lee Bright, former congressional candidate Richard Cash, and the first female graduate of the Citadel, Nancy Mace. If Graham doesn't clear 50 percent of the vote in the primary, there will be a two-candidate runoff.

Graham has been a leader of the GOP push for comprehensive immigration reform -- an issue that divides Republican voters. He won his 2008 primary against former Republican National Committeeman Buddy Witherspoon 67 percent to 33 percent.

Overall, Graham's approval rating is underwater, with 37 percent of all registered voters viewing him favorably and 47.5 percent viewing him unfavorably. He has generally not been considered a top Democratic target in 2014.