COLUMBIA, S.C. -- While it doesn’t receive the early attention that Iowa and New Hampshire get in presidential primary politics, South Carolina holds this important distinction: its winner has gone on to capture every Republican nomination since 1980.

The most recent Winthrop University poll, released less than two weeks ago, showed Texas Gov. Rick Perry leading with 31% and Mitt Romney a close second with 27.5%.

That might be surprising to some, who see South Carolina as not much more than a socially conservative state. But understanding the different kinds of conservatives who live here -- whether in the Upstate (dominated by social conservatives), the Midlands (the Republican power center with its mix of establishment Republicans and military voters), and Lowcountry (with its strong military presence and fiscally minded Northern transplants on the coast) -- are key to winning the Palmetto State’s GOP presidential primary.

“South Carolina is not a monolithic place,” said Mark Tompkins, a political science professor at the University of South Carolina. “It’s conservative for sure, but there are all these different strains of conservatism.”

As candidates try to outdo each other’s conservative credentials here, the 2008 South Carolina primary election serves as a reminder that it’s not always the most conservative candidate who wins the state.

“It helps to be able to appeal everywhere,” said Warren Tompkins, a longtime presidential campaign adviser, who is not affiliated with a candidate this cycle (and is no relation to the aforementioned Mark). “And, generally, whoever gets the plurality runs fairly decently across the board.”

Not always the most conservative candidate who wins
When John McCain won in 2008, he did so with just 33% of the vote -- and with a little help from Fred Thompson. McCain, a war hero, was able to dominate in the Midlands and Lowcountry.

Mike Huckabee, who finished second with 30%, won the biggest share of the state’s self-declared evangelical voters, which made up 60% of voters in 2008, according to exit polls, but Thompson siphoned off a crucial 15% of those voters -- and split the vote with Huckabee in the Upstate counties. Huckabee’s campaign argued at the time that Thompson’s 16% overall finish likely cost Huckabee the election.

“We got awful close,” Huckabee said in 2008 after the results were finalized.

The Upstate: Where God and country matter
It comes as no surprise that Huckabee, a former Baptist minister, was able to sell a Christian conservative message in the heavily evangelical Upstate. The region is home to Bob Jones University, which calls itself “the foremost fundamental Christian University.”

The Upstate’s focus on social issues was evident when Perry campaigned there recently. A woman congratulated him for saying evolution was a theory. “Well, God is how we got here,” Perry responded.

Romney, who finished fourth in South Carolina in 2008 with 15%, has largely kept his distance from the area. His religion -- he’s Mormon -- was a hurdle, especially in the Upstate, where he received as little as 8% in some counties. It remains to be seen if he rethinks sidestepping the state, given his standing in the Winthrop poll and Perry’s recent stumbles.

The Upstate isn’t just a key place for candidates to burnish their socially conservative credentials. It also contains some of the most voter-rich counties in the state. Republican consultant Chip Felkel, who worked on both of George W. Bush’s campaigns, pointed out that 52 percent of the 2008 primary vote came from seven counties – three of which are located in the region, including Greenville, which had the highest overall turnout.

In order to win in South Carolina, “you don’t necessarily have to be ardent on the social issues like a [Rick] Santorum, but you have to have bona fides on the social issues in order to take care of those votes in the Upstate,” said Felkel, who is unaffiliated but would have worked for Haley Barbour if he had decided to run.

The region has also always been a business hub for the state, first with tobacco farming, then textiles, and now through companies like BMW, whose only American factory is in Spartanburg. That environment breeds a sort of libertarianism, inherited from farmers who were wary of, as Mark Tompkins put it, “pointy-headed bureaucrats in Washington telling us we have to do all these things about tobacco.” That fits well with the present-day Tea Party.

The Midlands: A GOP establishment power center
In addition to dominating in the Lowcountry, McCain made up for his shortcomings in the Upstate also by almost sweeping the Midlands, an area Mark Tompkins describes as a “melting pot.” It has a strong military presence, including Shaw Air Force Base and Fort Jackson, the Army’s largest basic training center, helping McCain win nine of the area’s 10 counties.

The Midlands is also home to the state’s capital city, Columbia, as well as the University of South Carolina, the flagship institution of the state’s college system. Columbia is also a stronghold for African-American Democrats. Black voters make up more than half of Democratic primary voters, and churches here were must-stops in 2008 for Barack Obama and Hillary Clinton, who drew huge crowds. Two historically black colleges, Allen University and Benedict College, are also located in the capital city.

The Lowcountry: Beach, business, and the military
The Lowcountry has experienced an influx of Northerners -- largely retirees attracted to South Carolina’s home prices. For example, the population of Beaufort County, which includes the beach community of Hilton Head, surged by 34% over the past 10 years, according to the 2010 Census. Mark Tompkins characterized Lowcountry political strain as “business conservatism,” bolstered by “a bunch of rich Yankees in retirement homes.

As in the Midlands, the military has a big presence in the Lowcountry, with Air Force and Coast Guard bases, a Marine Corps Air Station and the Parris Island Marine Corps training grounds. That combination of military and older, more moderate voters helped McCain win six of the eight counties associated with the region.

Romney finished second in two of the counties, Beaufort and Charleston. His most recent of his infrequent trips to the Palmetto state this cycle took him, in fact, to Charleston. Charleston is also the home of a new Boeing plant, the subject of a National Labor Relations Board lawsuit alleging Boeing built the plant here in order to punish striking union workers in Washington State. Like all Republican candidates looking to curry favor with leaders in this non-union state, Romney railed against President Obama’s NLRB appointments, calling them “an egregious example of political payback.”

This time around, the region could be up for grabs -- if Romney decides to play in the state. He has the business experience, but Perry’s military experience (and Romney’s lack of it) is a hurdle.

The numbers coming out of the state are still “very fluid” and decisions about allocating resources in South Carolina and other primary states are ongoing, said Kevin Madden, an informal Romney adviser, who served as his 2008 communications director.

But, Madden added, “Rick Perry’s meltdown with conservatives around the immigration issue has hurt him there, and his positioning on Social Security is devastating with older voters and retirees. All of that makes it a competitive race.”

Romney will make more stops in South Carolina, but don't expect him to campaign here very heavily. Florida's primary is likely to be held just days later, and because of early voting, it's possible that as much as half of Florida's vote could be in by the time South Carolina's primary takes place.

The temptation to play here could also be a trap. Felkel believes Perry has the best chance to garner majorities from all corners of the South Carolina map.

“The state is tailor-made for Rick Perry,” Felkel said. “Because he gets the business community; he’s got military background, social conservatives like him, and he’s got that independent streak that Carolinians seem to like. Case in point, John McCain.”

NBC's Domenico Montanaro contributed reporting to this story.