South Carolina Sen. Jim DeMint's resignation to take over as the president of the Heritage Foundation stunned the political world on Thursday and, in the process, raised a series of fascinating questions about his future, the Senate and the future of the conservative movement.

"It’s a creative, innovative move, and demonstrative of the newer way of thinking about how to use new tools today to move an agenda, where service in government is just one way, but not the only way, to drive the conversation," said Eric Ueland, a former Senate chief of staff and now a lobbyist with the Duberstein Group.

That way of thinking marks a sea change from even a decade ago when the idea of DeMint abandoning his relatively prime perch in the Senate -- he had built a sort of conservative hub within the GOP conference -- to head a think tank (even one that pays as well as Heritage) would have seemed unthinkable.

But, the past decade has shown the influence that figures outside of elected office -- Rush Limbaugh, Grover Norquist to name two -- can have on the shape and direction of the conservative movement.  Serving in the House or Senate is no longer -- in a world of social media, 24 hour cable news heavily focused on politics and online grassroots organizing -- the sine qua non for a conservative wanting to push his (or her) ideas on a national level.

"He sees his role now as working with the grassroots on the outside to bring out real change in Washington," said Matt Hoskins, a longtime political adviser to DeMint who now runs the Senate Conservatives Fund, a super PAC once affiliated with the South Carolina senator. "It also means that Republicans have a strong leader on the outside to support them when they do what's right and hold them accountable when they don't."

Those who know DeMint say the move from the inside to the outside is broadly consistent with his career -- both before he won elected office in 1998 and during his time in the House and Senate. DeMint was a small businessman prior to winning the Upstate 4th district in 1998 and, particularly during his time in the Senate -- where he was elected in 2004 -- he focused less on legislating than cultivating the conservative movement from the ground up.

"It’s no secret that he spent much more time on grassroots advocacy and campaigns than he did on legislating," said one senior Republican Senate aide granted anonymity to speak candidly. "He clearly was not drawn towards the nuts and bolts of lawmaking."

What, ultimately, will DeMint's Senate legacy look like? That depends on what you think of DeMint.

His allies insist that he did nothing short of transform the Republican Senate conference from a center-right body into a conservative one -- thanks to the election of the likes of Sens. Rand Paul (Ky.), Mike Lee (Utah), Pat Toomey (Pa.) and Marco Rubio (Fla.) to name a few. DeMint was a strong supporter of all four candidates and funneled super PAC money to their campaigns.

DeMint hinted at just that in his statement announcing his plans to step aside. "Now it’s time for me to pass the torch to someone else and take on a new role in the fight for America’s future," DeMint said. (Click here to read his full statement.)

Added conservative blogger Erick Erickson in an email message to supporters: "Without Jim DeMint we would most likely not presently have in the United States Senate Pat Toomey, Rand Paul, Mike Lee, Marco Rubio, Jeff Flake, Ron Johnson, and Ted Cruz. We would not have a Republican establishment that now worries conservatives might actually primary them."

For those less favorably inclined to DeMint, his Senate legacy will be defined by defeats in places like Nevada, Indiana and Delaware where the South Carolina senator played an integral role in supporting the more conservative candidate who won the GOP nomination but lost the seat to a Democrat in the general election campaign.

Regardless of where you come down on what DeMint meant to the Senate, it's quite clear that what the departure means for his own political future will be debated and discussed for weeks and months to come.

While DeMint's decision to step aside from the Senate immediately stoked talk of whether he was burnishing his outsider credentials for a possible presidential bid down the line, Hoskins poured cold water on that notion. "I don't think he has any plans to run for public office in the future," Hoskins said.

Time will tell.  But, it's hard to imagine DeMint fading into obscurity any time soon.

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