Jim DeMint, the senator from South Carolina, announced on Thursday that he was stepping down from the Senate to head the Heritage Foundation, a conservative think tank. With nearly four years left in his current term, the move came as an utter surprise, and will require South Carolina Gov. Nikki Haley to appoint a replacement until a special election can be held in 2014. DeMint, a Tea Party favorite who wields considerable influence on the far right, will also leave a leadership void in the Senate's conservative wing.

Why did he do it? In an interview with The Wall Street Journal just before his announcement, DeMint suggested that he could be more influential at Heritage than in the Senate. "This is an urgent time, because we saw in the last election we were not able to communicate conservative ideas that win elections," he said. Erick Erickson at RedState agrees: "DeMint's power in the conservative movement just grew exponentially. A man who was going to retire in four years anyway, will now be leading the conservative movement from its base of operations for years to come." 

The foundation where DeMint will carry on his work occupies a prominent place in conservative politics. "Heritage is commonly called a 'think tank,' but it's something far more complex than that — it is one of the largest grass-roots organizations in the world, with an astonishing 700,000-plus donors and supporters and a budget of $75 million," says John Podhoretz at Commentary. (Fun fact: It was once a champion of a health-care proposal called the individual mandate, which has since been deemed a harbinger of socialist ruin by conservatives.)

Less charitable members of the GOP have suggested that DeMint, one of the poorest members of the Senate, did it for the money

DeMint's legacy in the Senate also remains a source of division in the Republican Party. Minority Leader Mitch McConnell (Ky.) praised DeMint for his "uncompromising service," a backhanded compliment for a conservative firebrand who used his influence to prop up far-right candidates in several Senate primaries, many of whom went on to lose easily winnable general election races. On the other hand, some credit him with ushering in a new generation of conservative leaders into the Senate. "Without Jim DeMint we would most likely not presently have in the United States Senate Pat Toomey, Rand Paul, Marco Rubio, Jeff Flake, Ron Johnson, and Ted Cruz," says Erickson.

At any rate, the news of his departure was met with genuine consternation among conservatives. "There's no doubt conservatives will have to work through a lot of disappointment," says Byron York at The Washington Examiner. Erickson, putting on his bravest face, even compared DeMint's departure to Obi Wan Kenobi being struck down by Darth Vader, only to emerge more powerful in death. (For good measure, Erickson casts McConnell in the role of Vader.) However, the guessing game has already begun over who will replace DeMint, with Rep. Tim Scott seemingly becoming an instant frontrunner. If appointed, Scott would be the only black member of the Senate, a striking irony given the Republican Party's deep unpopularity among black voters.