CONWAY, SC (WBTW) – With South Carolina at the center of the Democratic presidential race this week, two professors are sharing the history of the Palmetto State’s primary.

A debate will be held in Charleston on Tuesday and candidates will also be traveling all over the state before Saturday’s primary, which is expected to have a huge impact on the rest of the campaign.

“People are going to drop out after South Carolina,” said H. Gibbs Knotts, a political science professor at the College of Charleston. “There’s going to be fewer people and South Carolina has an added effect because a whole pack of southern states go after it.”

Knotts and Jordan Ragusa, who’s a political science associate professor at CofC, say they’ve written the first book on South Carolina’s primaries. It’s called “First in the South: Why South Carolina’s Presidential Primary Matters.”

They spoke about their book at Coastal Carolina University on Monday.

“National media come in, they come in from Los Angeles and New York,” Knotts said. “They want to know, ‘Where should I get barbecue?” and, ‘What does it take to win in South Carolina?'”

The professors say the answer to why South Carolina matters is that the voters resemble the Democratic and Republican parties.

“South Carolina Republicans kind of look like their national counterparts in ways that Iowa and New Hampshire don’t,” said Ragusa. “On the Democratic side, of course, the importance of the South Carolina primary lies in its large percentage of African American voters.”

Both parties in the state held caucuses until the Republicans moved to a primary in 1980 to attract more voters and Democrats eventually followed them in 1992.

“Democrats dominated South Carolina politics in the 1970s and Republicans got lucky,” Knotts said. “They ended up getting the primary in the books and also had a really dynamic, important election.”

Knotts and Ragusa say the winner of South Carolina’s Democratic primaries became the party’s nominee five out of six times. Former North Carolina Sen. John Edwards won in 2004, but then-Massachusetts Sen. John Kerry became the nominee.

The Republican primary’s winner eventually became the GOP’s nominee seven out of eight times, except for former Speaker of the House Newt Gingrich, who won South Carolina in 2012, but lost the nomination to Sen. Mitt Romney.