So, who will fill that void? While there are a few possibilities, there is perhaps a stronger argument to be made that no one will. Below are some names that seem like the likeliest possibilities, along with some reasons why they could well chart very different paths from the soon-to-resign senator:
* Sen. Mike Lee (R-Utah): Lee might be the most likely to embrace a DeMint-style role. He unseated fellow Republican Robert Bennett by running to his right in 2010, and, given Utah's strong GOP tilt, Lee won't have to moderate his views to ensure his political survival in future elections. (In Democratic-leaning states like Pennsylvania and Wisconsin, conservative Sens. Ron Johnson and Pat Toomey, for example, must at least consider their more mixed electorates.) What's more, Lee's shown no interest in running for president, which means he probably won't adjust his conservative views according to the national climate as much as some other Republicans who are eyeing national bids. All that said, Lee has a ways to go before he can become as big a force as DeMint on the campaign trail. As DeMint did, Lee started a leadership PAC from which he has supported other conservative candidates. But it has some work to do before it can begin to wield the same influence that the Senate Conservatives Fund has demonstrated in Republican primaries. Lee's PAC raised only about $160,000 during the 2012 cycle.
* Sen.-elect Ted Cruz (R-Texas): In a 2012 cycle full of disappointments for Senate Republicans, Cruz was the rare bright spot. He's a young, telegenic, Cuban-American conservative with a compelling biography and a big upset under his belt against Lt. Gov. David Dewhurst (R). When your stock is so high, though, everyone wants to be your friend. And if Cruz wants to leave the possibility of higher office open -- something he might be well-positioned for in the coming years -- he'd be well-served not to make any early enemies in the party. He's already demonstrated a willingness to play a conciliatory role in the GOP by joining Senate Republcians' campaign arm as a vice chairman to incoming chairman Sen. Jerry Moran (R-Kan.). A big part of Cruz's role at the National Republican Senatorial Committee will be to try to bridge the gap between Senate Republicans and the conservative groups that supported his candidacy.
* Sen. Rand Paul (R-Ky.): Paul is popular among conservatives, and with the upcoming retirement of his father -- former presidential candidate Rep. Ron Paul (R-Texas) -- he is well-positioned to inherit the leadership of a vocal and visible wing of the conservative movement. He is also not afraid to buck his party's leadership when he disagrees, which is often. But he is thinking about running for president. "I'm not going to deny that I'm interested," the senator recently said. It's difficult to imagine somebody considering running for president taking a keen interest in Senate primaries or wanting to paint his or her self into a corner in the upper chamber. (For this reason and others, Sen. Marco Rubio (R-Fla.) is not a DeMint-like figure. While he's deeply popular among conservatives, we simply can't see Rubio wanting to become anywhere near as strictly defined as DeMint.)
Who did we miss? Who might be the next DeMint?