South Carolina Sen. Jim DeMint (R) announced Thursday that he would resign from the Senate in January to become president of the conservative Heritage Foundation in Washington, D.C.
DeMint's unexpected resignation subtracts one of the Senate Republican conference's foremost immigration hawks just before Congress is expected to tackle a comprehensive immigration reform effort next year.
"It's been an honor to serve the people of South Carolina in United States Senate for the past eight years, but 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 in a statement. "I'm leaving the Senate now, but I'm not leaving the fight."
DeMint placed himself at the center of the fight over the last comprehensive immigration reform bill in 2007, leading a conservative Republican faction against the bipartisan effort supported by President George W. Bush and dozens of congressional Republicans and Democrats.
"If [Bush] continues to push this bill in spite of the way the American people feel about it, I think that's more likely to undermine him,'" DeMint told CNN in June 2007.
"In early 2007 DeMint also fought for common-sense immigration reform by leading the effort to defeat the amnesty bill and calling on government to first secure our borders, enforce the laws already passed, and streamline the legal immigration system," reads his official Senate biography.
DeMint continued to advocate for tough immigration enforcement measures in the next Congress. In 2010, he attempted to pass an amendment that would have required the government to complete 700 miles of fencing along the U.S.-Mexico border within one year. During one such effort to attach the amendment to a separate piece of legislation, he compared illegal immigration to an oil leak.
"If any member of the Senate stood up today and said that we should not seal the oil leak in the Gulf until we have a comprehensive plan to clean it up, we would all say that that is absurd. Certainly we need to seal that leak as quickly as possible to minimize the cleanup later," he said. "But that is exactly the kind of logic that the president and my Democratic colleagues are using when it comes to immigration."
Pro-immigration reform advocates cheered DeMint's departure, since he played influential role in rallying conservative opposition to the last immigration overhaul.
"The chances for immigration reform with a pathway to citizenship for 12 million undocumented people just went up," Frank Sharry, executive director of America's Voice, told ABC/Univision. "It's good news for us."
Opponents of immigration reform that provides relief to undocumented immigrants said that DeMint will be missed, but expressed confidence that other senators could fill the leadership void.
"He was obviously a very stong leader for true immigration reform in his time in Congress, and he will be missed," said Ira Mehlman, a spokesman for the Federation for American Immigration Reform (FAIR). "There are other strong voices in the Senate, and in terms of blocking amnesty, it's the votes that count."
Mehlman suggested that DeMint could still influence the debate in his new position at Heritage.
"We expect he's going to continue to be a strong voice for immigration reform there, have great or even greater influence there than he had in the Senate," he said.
DeMint was also instrumental in helping elect so-called Tea Party members to the Senate in 2010 who would ostensibly reject compromises on conservative principles.
But coming off an election in which Latino voters largely abandoned the Republican Party, some of the senators DeMint endorsed have spoken about the need to pass some sort of immigration reform, including Rand Paul (R-Ky.) and Marco Rubio (R-Fla.)
DeMint's resignation is no guarantee that his successor will have different views on immigration, but advocates said that he's unlikely to wield the same influence as DeMint. The timing of the senator's departure carries significant consequences heading into next year.