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Sen. Jim DeMint, R-S.C., shocked Washington last week when he announced that he will quit the Senate to become president of a think tank. But as the barriers crumble between policy research and partisan advocacy, the building blocks are there for DeMint and the conservative Heritage Foundation to build a powerful operation with political clout.

DeMint explained on Rush Limbaugh's show why he decided to give up his Senate seat to lead Heritage.

"It was the Heritage Foundation that inspired me to run for Congress," he said.

As Heritage guided DeMint in ideology and policy, he helped to bolster the ranks of its allies.

Ted Cruz, the newly elected Republican senator from Texas, congratulated DeMint on his new role, saying DeMint's "combination of brilliance, principle, common sense, creativity and — above all else — courage will be an ideal fit for the conservative movement's leading think tank."

Cruz got to the Senate by knocking off an establishment Republican in a primary last summer — something he did with help from DeMint.

"I've never been more excited about supporting a candidate as I did Ted Cruz," DeMint has said.

Up until now, DeMint has had an organization that offers more than just words: a leadership committee that backed candidates he endorsed, and this year a superPAC allied with DeMint that bought ads promoting Cruz.

When Cruz declared victory, he said thanks — as did Sens.-elect Deb Fischer of Nebraska and Jeff Flake of Arizona. In 2010, DeMint helped to elect five senators.

DeMint and his organization helped ultraconservatives take out more moderate Republicans in primaries.

Now DeMint will most likely have to leave that behind. Heritage is a 501(c)(3) charity, and it cannot engage in electoral politics. But Heritage offers a different path to political engagement. It has an affiliated group, Heritage Action for America, which is a 501(c)(4) social welfare organization. That means it is allowed to talk about candidates.

This is unusual among think tanks, which generally try to avoid the partisan combat. At Heritage, people believe the world of think tanks is changing.

Vice President Michael Franc, who is on the board of Heritage Action, says it's because the political parties have become more ideologically pure.

"The role is different. I think the kind of institutions that tend to get a little bit more attention in this new kind of world are the ones that are heavily engaged in the tactical side of the debate," he said.

How much more engaged?

In a recent video, Heritage Action CEO Michael Needham begins by calling President Obama's re-election devastating and later says, "We are in a war."

"In 2014, there'll be 20 Senate liberals up for re-election. A strong constitutionally conservative Senate is critical for this fight," he says. "And in 2016, with a deep bench of committed conservatives, we must choose a nominee who can best articulate our shared conservative values."

Heritage Action campaigned in seven races this year. Its candidates lost in five of them. But it appeared to be badly underfunded.

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