Just about everyone who works in South Carolina politics was taken aback by Jim DeMint's announcement Thursday that he will resign his Senate seat in January to become president of the Heritage Foundation.
There was no shortage of theories about why the influential conservative stalwart decided to leave his office with four years remaining in his second term.
Whether it was a desire to affect his agenda from outside the confines of a minority party on Capitol Hill, the hefty increase in his paycheck that he is now likely to receive, a long-term strategy to seek opportunities for national office, or all of the above, there is no doubt that the implications of DeMint's departure will be far-reaching on both state and national levels.
The most immediate task now falls upon South Carolina Gov. Nikki Haley -- who is herself up for re-election in 2014 -- to appoint a temporary replacement for DeMint.
And among the most pressing questions inherent in that decision is how the appointee will affect the political prospects of his South Carolina Senate colleague, Lindsey Graham. The two-term lawmaker has endured criticism from the conservative wing of the Republican Party over his recent comments expressing a willingness to break Grover Norquist's anti-tax pledge as well as previous breaches with rank-and-file GOP orthodoxy on issues like immigration reform and climate change.
South Carolina has no shortage of ambitious conservatives rumored to be eying a primary challenge to Graham in 2014, though none has thrown his hat into the ring yet.
Despite his potential vulnerabilities, Graham has powerful allies, a substantial war chest, and has proven an effective campaigner in the past. And anyone who had been considering the difficult challenge of a primary run against an incumbent senator may now be more inclined to vie for the open Senate seat special election that also will be held in 2014.
"At first blush, you'd have to say the happiest person in South Carolina today is Lindsey Graham," said South Carolina GOP operative Joel Sawyer.
At second blush, however, the situation appears to be more complicated, and much rests on Haley's decision.
The South Carolina governor might appoint a so-called "caretaker" -- likely an elder statesman who would be willing to serve for two years and then step aside without running for the rest of DeMint's term in 2014.
Under this scenario, former South Carolina Attorney General Henry McMaster likely would be at the top of the list of potential appointees. After finishing in third place in the 2010 Republican primary for governor, McMaster endorsed Haley in her successful run-off that year against Gresham Barrett and is known to have maintained a good relationship with her.
Alternatively, Haley could choose to appoint someone like South Carolina Rep. Tim Scott -- a relatively young conservative favorite and DeMint protégé who is widely believed to have ambitions beyond his current House seat.
Scott has been the most frequently mentioned name in the discussion of possible primary challengers to Graham and could be a viable contender in a one-on-one situation.
"The danger for Graham is that in a perfect-world scenario, he wants as many challengers as possible because if they're all beating each other up and jockeying for position, that benefits him, and what he doesn't want is a two-person race early in the process," Sawyer said. "You have to remember that in Columbia, South Carolina, the plausible becomes fact faster than in any place in the nation."
Indeed, any effort to game out how each scenario will play out for Graham remains mired in uncertainty, as the incumbent senator is not the only one in the game with complicated political interests.
Conservative activists on Thursday wasted no time in touting Scott as the best person to replace DeMint, who is known to be fond of the Tea Party-backed first-term congressman.
But Scott was just last week appointed to a plum position on the House Ways & Means Committee and may not be anxious to walk away from that opportunity to serve a Senate stint that is guaranteed for just two years.
Amid what is almost certain to be intra-party turmoil, the 2014 election cycle will no doubt be a fascinating one in South Carolina, as every congressional and statewide seat will be up.
"Honestly, I think people are going to come out of the woodwork for it," South Carolina GOP operative Mike Campbell said of the open Senate seat. "And anyone who thinks it'll be easy for someone to beat Lindsey, it'll be a very tough feat down here."
In making her appointment to replace DeMint, Nikki Haley's own political fate will be among the key factors for her to weigh.
Her speech at the Republican National Convention earlier this year was widely praised, and she remains well-regarded in many GOP circles as future presidential candidate material, but her relationship with Republican state legislators has at times been rocky.
A Winthrop University poll released on Wednesday found Haley's approval rating remains under water at 38 percent, and her next move will be an important opportunity for her to regain voters' confidence.
"A lot of people are assuming a lot of things," said Charleston-based Republican consultant Jim Dyke. "The first thing we're going see is that Gov. Haley is independent and thoughtful and is going to do what she thinks is in the best interest of the state of South Carolina."
More from RealClearPolitics: