Haley, a three-term state House member, criticized Sheheen for not being in the Senate in March during votes on a proposed constitutional amendment aimed at keeping unions out of the state. The measure received final approval from legislators in March and will be on the November ballot.
It is meant to guarantee secret-ballot elections for workers deciding whether to unionize, in a state that already has strict anti-union laws.
Supporters of the anti-union measure say it is aimed at pre-empting proposed federal legislation that would make it easier to unionize by allowing a majority of workers to create a union by signing cards, which they argue leaves workers open to intimidation to unionize.
South Carolina ranks 49th nationwide in union membership, accounting for fewer than 4 percent of workers.
Sheheen's campaign says he supports secret-ballot rights as a way to keep South Carolina business-friendly.
His spokesman, Trav Robertson, said Haley has no room to criticize his absence, noting that Haley missed plenty of votes herself, including more than half of the roll call votes this year on the House floor. He couldn't immediately explain why Sheheen was absent on the anti-union measure, but he pointed to the state Chamber of Commerce's endorsement of Sheheen as evidence he's not pro-union.
"We've heard Nikki Haley say people who live in glass houses shouldn't throw stones. She's living in a glass house. The only person who doesn't show up for important votes is Nikki Haley," Robertson said.
ACCORDING TO House records, Haley missed every meeting this year of the House Education and Public Works Committee, and those of the higher education and motor vehicles subcommittees to which she was assigned.
As Sheheen pointed out in a debate earlier this week, she also missed voting last October on economic development incentives for Boeing, which led the company to locate its 787 assembly plant in North Charleston, instead of Washington state. Sheheen called it the state's biggest economic development win in decades.
Haley said she was there when it mattered this year, such as for the anti-union measure, to which she signed on as a co-sponsor. House records show she did attend committee meetings in 2009.
"I think we were both running for governor, but I made a point to be there for as many of those floor votes as I could," Haley said.
"Subcommittees were not something that we, I mean, that's a choice that we chose not to focus on. But I made sure that the votes that matter, which were the votes on the floor, I was there for," she said.
ON THE MISSED Boeing vote, she said it was during a two-day special session, and she had a previously scheduled event. She put a note in the official House journal that she would have voted yes, had she been there.
Haley pointed to Boeing's decision in advocating the anti-union measure. The state's anti-union reputation is a great asset, she said.
"It's the reason Boeing came," Haley said in her campaign headquarters, standing alongside Attorney General Henry McMaster and the GOP nominee to replace him, Alan Wilson. "It's the reason companies look to South Carolina, and it's something we need to keep in place."
A group of nine Democratic senators, which did not include Sheheen, put a statement in the Senate journal opposing the measure as opening up the state to a costly federal lawsuit during a fiscal crisis.