11:28PM EST December 6. 2012 - WASHINGTON — Republican Sen. Jim DeMint of South Carolina, who stunned his colleagues when he announced Thursday he will leave the Senate to head a conservative think tank, said he expects his successor to be named within the next week.

DeMint's replacement in the Senate will be selected by South Carolina Gov. Nikki Haley, a Republican.

In an interview Thursday in his Capitol Hill office, DeMint said the decision is completely up to Haley."I told Governor Haley that I would support her recommendation and that I trusted her," he said. "It's her decision, not mine."

Rob Godfrey, a spokesman for Haley, declined comment on whom she might name."Today is about Sen. DeMint's service to our state and nation, and that's where the focus should remain," he said.

DeMint, a hero of the tea party movement who occasionally clashed with GOP leaders he found insufficiently conservative, will leave the Senate in January to take the top job at the conservative Heritage Foundation. The foundation, based in Washington, said DeMint will take over as president in April. DeMint will manage a staff of 250 with an annual budget of more than $80 million.

DeMint was scheduled to complete his second term in January 2017. The person Haley will appoint will serve a term ending Jan. 3, 2015. A special election will be held Nov. 4, 2014 to fill the last two years of DeMint's term, and an election will take place in 2016 for the next full six-year term.

DeMint's plans to leave the Senate promise plenty of election-year drama in South Carolina in 2014. In addition to the special election to fill the last two years of DeMint's term, both Haley and South Carolina's senior senator, Republican Lindsey Graham, will be up for re-election that year.

Haley has a number of names to choose from in choosing DeMint's successor. South Carolina's congressional delegation includes GOP Reps. Mick Mulvaney, Jeff Duncan, Trey Gowdy and Tim Scott — all viewed as potential contenders for higher office. Scott, who is black, had been eyeing a run for governor and his name has come up frequently in news accounts as a possible DeMint replacement.

Other potential contenders include former ambassador David Wilkins, former South Carolina attorney general Henry McMaster, state Sen. Tom Davis, who served as chief of staff to former governor Mark Sanford, and state Treasurer Curtis Loftis.

DeMint did not express a preference for who should replace him. "Certainly I'm close to the delegation here so I feel good about them, but that doesn't mean there are not other people in South Carolina I would be happy with too," he said.

Haley told News Radio WORD in South Carolina on Thursday she will not appoint herself to replace DeMint.  Experts say Haley must decide whether to appoint a caretaker in the office or someone who would run for the seat during the special election in 2014.

Haley said DeMint "has served South Carolina and the national conservative movement exceptionally well. His voice for freedom and limited government has been a true inspiration."

DeMint said the deal with Heritage was reached Wednesday, which is what he indicated on ethics forms he filed about 11:30 a.m. Thursday. DeMint said he began notifying family and friends Wednesday night and called Haley Thursday morning. He also met with Graham a few minutes before addressing the staff at the Heritage Foundation.

Graham, in an interview off the Senate floor, said he was stunned by DeMint's news. "When he told me, I about fell off my couch," he said.

Graham said he hasn't had time to think about how his own political future will be affected by DeMint's departure. "Jim's biggest legacy I think is creating energy for those who believe in limited government," Graham said.

DeMint said he will support Graham from his new post at the Heritage Foundation. "Despite what people read back home, we've been great partners," he said. "We've worked the system pretty well ... He kind of throws things out and gets people all churned up, but if you look at his record, we generally vote the same way. He's a player and he's been fun to work with."

DeMint said his move to the foundation doesn't mean he's leaving his constituents behind. "I wouldn't be doing it if I didn't think the opportunity at the Heritage Foundation would allow me to do more to improve the lives of the people of South Carolina but also all over the country," he said, wearing a blue tie with the Heritage symbol on it. "I think I'll have more impact outside the Senate for South Carolina than if I stay."

He said his new job will be to sell policies at a national level that he believes "make life better for people — poor, rich, every race, in every family situation."

The Heritage Foundation was founded in 1973. Its web site says its mission is "to formulate and promote conservative public policies based on the principles of free enterprise, limited government, individual freedom, traditional American values, and a strong national defense."

"Jim DeMint has shown that principled conservatism remains a winning political philosophy," Heritage Chairman of the Board Thomas A. Saunders said in a statement. "His passion for rigorous research, his dedication to the principles of our nation's founding, and his ability to translate policy ideas into action make him an ideal choice to lead Heritage to even greater success."

DeMint first ran for the Senate in 2004 after limiting himself to three terms in the U.S. House. Although he was re-elected in 2010, he was never certain whether he would run for a third term. He will replace Ed Feulner as president of the Heritage Foundation. Feulner was paid just over $1 million in 2010, according to tax forms filed by the foundation.

DeMint, who earns $174,000 a year as a senator, is one of the least affluent members of the Senate. The personal financial disclosure form he filed in May this year reported individual retirement account assets for 2011 worth between $2,002 and $30,000.

It also says he earned $43,755 from a book advance last year and lists two residential mortgages, one between $100,000 and $250,000, and one between $250,000 and $500,000.

The Club for Growth, a conservative think tank that advocates for lower taxes and limited government, called DeMint "a champion of economic freedom (and) a defender of free markets."

The Senate Conservatives Fund, the political action committee that DeMint founded, issued a statement Thursday saying DeMint "has consistently fought for conservative policies and he's helped elect a new generation of conservatives who will continue this legacy."

DeMint used the fund to financially support the candidacies of conservatives such as Pennsylvania's Pat Toomey, Florida's Marco Rubio and Sen.-elect Ted Cruz of Texas. The fund was three-for-nine in picking conservative Senate candidates this year after spending more than $8.7 million.

DeMint is no longer affiliated with the fund, but comments he made after the 2012 election suggest tea party Republicans have no intention of compromising on core issues just because President Obama won a second term.

"We will certainly face many battles in Congress in the coming months that will give us the opportunity to clearly articulate the failures of liberalism and the common sense of conservative alternatives," DeMint wrote on his Facebook page. "We must not shrink from the fight on Capitol Hill or in drawing these distinctions for the American people, regardless of the attempted distortions by the mainstream press."