Democratic gubernatorial hopeful Vincent Sheheen talked to the Charleston Propeller Club tonight, but as with his recent appearance before the Charleston Rotary Club across Hagood Street, Sheheen stood alone.

His Republican opponent, Nikki Haley, was invited to both events, but passed because of scheduling conflicts.

The lack of their joint appearances in Charleston shows how undecided voters, particularly in the Lowcountry, will have relatively few chances to see the two candidates debate or even appear side by side.

The two are set to debate later next month in Columbia and Florence, and a third debate could be added in the Upstate. An attempt to schedule a Charleston-area debate apparently unraveled because Sheheen was not willing to debate at Porter-Gaud School, a private school, Sheheen campaign manager Trav Robertson said.

Asked if he were frustrated about the lack of debates -- Sheheen has proposed holding five across the state -- Robertson said, "It's not about frustration. It's that Nikki Haley is hiding from the people of South Carolina."

But Rob Godfrey, Haley's campaign spokesman, said while a scheduling conflict kept Haley away tonight, she visited with the Propeller Club before the June 8 primary "and looks forward to discussing the port with them again soon."

Haley's absence came up briefly during Sheheen's rapid fire question-and-answer session with Robert New of the club. Sheheen noted Haley has traveled recently to Texas, Chicago and Philadelphia. "My opponent is running for Governor of the United States," he said. "I spend my time in South Carolina. I spend my time with people like you."

Godfrey said both Haley and Sheheen do some fundraising out-of-state. "The fact that Nikki is more well-liked than Vince both in-state and out-of-state is something for the Sheheen campaign to be concerned about it," he added.

With polls showing Haley maintaining a lead over Sheheen, it's not surprising that there are relatively few debates on tap, said political science professor Robert Oldendick of the University of South Carolina.

"Typically if you've got front-runner status, your strategy is to limit the number of joint appearances," he said, adding that such appearances not only put both candidates on an equal footing but also can create a chance for some mistatement or contrast that could harm the front-runner.

"Why introduce an unknown into the mix?" he added.

Sheheen said tonight he would fight for a congressional earmark so the U.S. Army Corps of Engineers could study deepening Charleston Harbor. Haley -- like U.S. Sen. Jim DeMint -- opposes such earmarks.

But Godfrey said Haley considers the port "a vital part of South Carolina's economic future, and whether the funding comes from the federal government, state government, or elsewhere, ensuring long-term strength of our port system will be one of Nikki's top priorities as governor."

Reach Robert Behre at 937-5771.