GREENVILLE, S.C. — Jeff Duncan, the popular and very conservative representative from South Carolina's 3rd Congressional District, has never had three presidential candidates appear at his annual Faith and Freedom Barbecue. But tonight, at the Civic Center in Anderson, S.C., he's welcoming Ben Carson, Ted Cruz, and Scott Walker -- and fueling a lot of speculation about who has the best chance to win South Carolina's first-in-the-South primary.

Who's leading the race right now? Donald Trump, just like everywhere else. But South Carolina, for a variety of reasons, has a paucity of polling compared to Iowa and New Hampshire. The last poll was taken about three weeks ago, and there haven't been very many surveys all summer.

For example, there have been 10 polls of Iowa Republicans taken since June 1, according to the RealClearPolitics average of polls. There have been nine in New Hampshire. But there have been just four in South Carolina in the same period. "The national press interest in Iowa and New Hampshire, and the national polls, have the effect of keeping the later states quiet," says Clemson political scientist David Woodard, who conducts the respected Palmetto Poll. But South Carolina's role in the primary season is "crucial," Woodard says, because "South Carolina is arguably the first 'red' primary state (Iowa and New Hampshire are in play each fall) and because Romney won no southern primaries four years ago."

The most recent poll, three weeks ago, by the August Chronicle showed Trump with a big lead, followed by Bush, Carson, Huckabee, Graham, Walker, and Cruz. But that was before the Aug. 6 Republican debate that to some degree reshaped the GOP race. Two of Duncan's guests — Carson and Cruz — moved up as a result of the debate, while the third, Walker, moved down.

For all the speakers, Duncan's event is an opportunity to make an impression in the state that has long styled itself on "making presidents." For years, South Carolina Republicans took pride that the winner of their primary always went on to win the GOP nomination. That changed in 2012 when Newt Gingrich won the primary, but they are hoping to get back on track this time around.

Of the three speakers at Duncan's event, many South Carolina Republicans are particularly eager to see Carson. "He is a hot commodity," says one unaffiliated state political insider. "He hasn't been over-exposed in South Carolina. A lot of people in the evangelical community want to see him."

"If there's a problem with Carson," the insider continues, "it would only be whether or not a lot of the folks who agree with him ideologically are possibly looking for an angrier advocate. He's more of a soft-spoken, thoughtful speaker, and that may not be the tone they're looking for."

Cruz is likely to be the same Ted Cruz who has been picking up momentum, most recently on a 21-state bus tour through the South after the RedState Gathering in Atlanta. Cruz's message of conservative authenticity — always has been, always will be — plays well with GOP base audiences.

The question mark is Walker. Some South Carolinians note that they wanted Walker to show them more at the debate, and he failed to do so. Now, Walker is reshaping his message into a more explicitly anti-Washington appeal, specifically taking on the Republican leadership in Congress. That could be effective, but of course Walker, when he delivers that message in South Carolina, will have to except his host, Duncan, from the charges.

Duncan invited Carson, Cruz, and Walker in part as the result of an informal poll he took on his website, JeffDuncan.com. He took Rand Paul, Marco Rubio, and fellow South Carolinian Lindsey Graham out of the mix because they appeared at the event the last two years.

Graham, as a favorite son, presents a bit of a dilemma to Duncan and other South Carolina politicians. Duncan is perhaps the most conservative of a very conservative South Carolina delegation in Congress; he is the only South Carolina Republican who voted against John Boehner to be Speaker of the House. A politician of his ideological profile is not likely to support Graham. Plus, Duncan did not endorse any candidate in 2012. So don't look for a Duncan endorsement of his fellow South Carolinian. Who will get the nod for 2016 could depend a lot on Monday night.