This article was originally published by heartland.org.

Lindsey Graham’s support for global warming restrictions is taking center stage affecting the incumbent U.S. Senator’s bleak poll numbers in his bid to survive a primary challenge in the 2014 elections.

Graham is well below the 50 percent threshold in a recent poll of likely Republican primary voters in South Carolina, conducted by Landmark Communications and Rosetta Stone Communications. Only 42 percent of likely Republican primary voters said they support the incumbent Graham. Graham’s poor support among Republican voters is remarkable considering Graham’s primary opponents have relatively little name recognition throughout the Palmetto state.

Graham’s primary opponents are hammering the incumbent for frequently straying from conservative principles, and they are hammering Graham particularly hard for his longstanding support for global warming restrictions.

State Sen. Lee Bright, who tallied the most support among Graham’s primary opponents in the poll, put Graham’s global warming advocacy at the top of the list among Graham’s shortcomings in an interview with Breitbart News.

“Lindsey Graham’s record of promoting cap and trade, banker bailouts, liberal Supreme Court justices, and amnesty have driven a wedge between him and conservative voters in South Carolina, in spite of his relentless courtship of the mainstream media,” said Bright.

Graham’s global warming advocacy puts him on a similar political trajectory with former U.S. Rep. Bob Inglis. Like Graham, Inglis was a South Carolina Republican who championed global warming restrictions in the U.S. Congress. In June 2010, Inglis’ global warming advocacy took center stage in the Republican primary. The incumbent congressman was humiliated in the primary contest, capturing only 29 percent of the vote in a head-to-head matchup with challenger Trey Gowdy despite Inglis benefiting from the advantages of incumbency.

If neither Graham nor any of his challengers captures a majority of the vote in the 2014 Republican primary election, the two highest vote-getters will square off in a head-to-head vote for the party’s nomination.

Graham appears to have his work cut out for him, and his support for global warming restrictions is about as helpful as a millstone tied around the neck of a shipwreck survivor trying to tread water in the middle of the ocean.