It’s been nearly two weeks since Mark Sanford placed first in South Carolina’s 1st district Republican primary and kicked off a runoff campaign as the heavy favorite to win his party's nomination.

Little has changed since that time.

With Election Day coming up again on Tuesday, the former governor is the clear front-runner to defeat former Charleston County councilor Curtis Bostic.

Former governor Mark Sanford. (Bruce Smith/Associated Press)

There haven't been any “earth-shattering kabooms" during the runoff campaign, said South Carolina Republican strategist Luke Byars, who is neutral. He added: “As a result, I think Sanford’s still favored by a great margin.”

Richard Quinn, a second neutral GOP strategist, said: “My guess is Sanford will win comfortably.”

Sanford won 37 percent of the vote March 19, while Bostic won just 13 percent, barely good enough to edge out the third-place finisher in the race. What followed was a fairly quiet and pretty one-sided runoff campaign.

Sanford, who is much better-known and better-funded, has been difficult to catch. The former governor has stuck to a steady message. He's running as a fiscal conservative, pointing to his record on spending as governor, and before that, as the 1st district representative.

"We're going to continue working right up to the wire getting our supporters out to vote and spreading the word about the governor's record of cutting spending and debt," said Sanford spokesman Joel Sawyer.

The Republican fell from grace dramatically in 2009, when, as governor, he disappeared from the state, then admitted to an extramarital affair. Voters in the 1st district are very familiar with the matter, and it hasn’t been a dominant focal point in the Bostic-Sanford back-and-forth.

The issue came up most prominently during a televised debate last week, only after the moderator raised it. Sanford admitted fault, and argued that the 2009 episode brought him humility that would serve him well on Capitol Hill. Without directly mentioning the matter, Bostic called Sanford a “compromised candidate.”

For the most part, Bostic’s been focusing on his own message in the runoff. With limited money and a very limited window of time, the personal injury attorney has, like Sanford, underscored his fiscal conservative chops. He’s also sought to build his base of Christian conservative voters.

“It certainly has been a David and Goliath race,” Bostic said in an interview. The underdog is using the final day of the runoff campaign to focus on his ground game, he said, and ensuring his strongest supporters turn out to vote.

Bostic's also  been announcing endorsements from Christian conservatives. Former presidential candidate Rick Santorum, who is popular with religious conservatives, stumped for him last week.

But Bostic’s base may be deeper than it is wide. Winthrop University pollster Scott Huffmon said that the 1st district isn’t an area where the Christian conservative vote can really turn a race.

“The low country has traditionally been the home to more of the fiscal conservatives, while the upstate has been the home to more social/religious conservatives,” Huffmon said. “This means that the district Bostic is running in may not be the district with the most people in his natural base.”

Both Sanford and Bostic can claim some support among the 14 other Republican contenders in the GOP primary, some of whom only garnered marginal support, coming mainly from their most loyal supporters.

Byars, the Republican strategist, said endorsements from lesser-known candidates in a crowded election don't mean that much because many of them inspired loyalists to vote for them two weeks ago. Those voters may have little interest in the Sanford/Bostic showdown.

"If there had been four or five candidates in the primary, you might have been able to argue that the endorsements of those specific candidates really mattered," he said.

About 53,000 voters turned out for the GOP primary. That’s low compared to a regular election, but higher than many strategists and observers had expected. Anticipating turnout for Tuesday is difficult, given the unique circumstances of a spring, off-year special election runoff.

One Republican said he thinks if turnout approaches what it was two weeks ago, it will be a troubling sign for Sanford, because he's unlikely to expand beyond the roughly 20,000 voters who opted for him in the primary election.

“Anything over 45,000 or so is bad news for Mark Sanford,” said Walter Whetsell, a Republican strategist whose firm worked for GOP candidate John Kuhn in the primary. Kuhn endorsed Bostic in the runoff.

The winner of Tuesday’s runoff will advance to five-week campaign against Democratic nominee Elizabeth Colbert Busch, the sister of faux-conservative commentator Stephen Colbert. The Republican nominee will begin as the front-runner, but strategists on both sides can foresee a competitive May 7 election. Though the district leans heavily Republican, Colbert Busch has raised money at an impressive pace and has built strong name recognition.

So if it’s Sanford vs. Colbert Busch, buckle up, because the next month could be even more interesting than the last one.