WASHINGTON — In typical blunt fashion, Sen. Jim DeMint recently warned of the dangers to America from the lame-duck 'zombie' Congress that's poised to resolve weighty issues such as the looming "fiscal cliff" before it adjourns at the end of the year.

The biggest threat is "the 'lame-duck' members of Congress ... who have either announced their retirement or been replaced by voters," DeMint, 61, wrote last month on his senatorial website blog. "These few dozen 'zombie' legislators, unlike their colleagues, are utterly free from public accountability."

With his impending departure from the Senate announced Thursday, DeMint, R-S.C., officially joined the zombie class. His 14-year congressional career will end when the 112th Congress completes its business.

But the South Carolina conservative won't be aimlessly roaming the political countryside. From his new perch at the Heritage Foundation, he'll very likely continue the role he carved during his Senate and House days as a cultivator and kingmaker of conservative congressional and presidential candidates — and occasional irritant to his party.

"South Carolina has a long tradition of colorful politicians who stand outside the mainstream," said Blease Graham, an emeritus University of South Carolina political-science professor, harking back to the late Sen. Strom Thurmond and bare-knuckle political guru Lee Atwater. "I think DeMint stands to take a place among that group."

Since he was first elected to the House in 1998 and the Senate in 2004, DeMint has been a drum major for fiscal restraint and conservative purity within the Republican Party in terms of policy and candidates.

His star rose around 2006, when he spearheaded the cause against targeted political spending known as earmarks, helped scuttle a drive for comprehensive immigration legislation desperately sought by President George W. Bush and later led the charge against President Obama's health-care law.

DeMint, a native of Greenville, S.C., used skills he developed as the former owner of a marketing company, and deftly labeled his targets. Comprehensive immigration became "amnesty" and he warned — incorrectly, as it turned out — that the health-care law battle would be Obama's "Waterloo."

DeMint's political-action committee (PAC), the Senate Conservatives Fund, drew big donations from hedge funds, manufacturers and the well-known conservative donors at Koch Industries.

In all, it gathered 4,740 contributions of more than $200, according to the Center for Responsive Politics. The PAC raised money — $13.7 million in 2012 — for a string of longshot conservative candidates, who often defeated mainstream Republicans in party primaries.

But in general elections, DeMint's people lost more often than they won.

In 2010, he helped nominate three Republicans — Sharron Angle in Nevada, Christine O'Donnell in Delaware and Ken Buck in Colorado — for Senate seats that had seemed within reach. All three lost their races.

To be sure, some DeMint-backed candidates such as Sens. Marco Rubio, R-Fla., Rand Paul of Kentucky, Mike Lee of Utah, Patrick Toomey of Pennsylvania and Ron Johnson of Wisconsin all are sitting at desks in the Senate chamber.

And some of DeMint's political children paid homage Thursday. "He created the opportunity for principled but underfunded candidates to have a chance," said Rubio, who was mentioned as a possible vice-presidential candidate this year and a potential presidential contender in 2016. "That was certainly my case. So I think the Republican conference is better for Jim DeMint's service."

Not all Republicans agree. DeMint often was at loggerheads with the party's election apparatus, which more often than not was looking for House and Senate candidates with the best chances of winning and leading the party to a congressional majority, instead of which candidates were more conservatively pure.

"The priority is not first the majority," DeMint said in 2010. "We had a big majority with 55 Republican senators. We had a big House majority. We had Bush in the White House. We spent too much, borrowed too much — and they (the voters) threw us out."

The defeat of DeMint's allies this year helped keep Republicans as the Senate minority and left DeMint with little trust from the GOP leadership. During DeMint's eight years in the Senate, none of the bills he has authored have been signed into law.

"He hasn't been terribly successful as a politician or as a senator," said Mark Tompkins, a political-science professor at the University of South Carolina who has followed DeMint's career. "At the end of the day, he just wasn't temperamentally a man of the Senate."

Meanwhile, DeMint has a few more weeks to roam the Senate chamber and halls in this lame-duck session before he joins his few dozen fellow zombies.

Material from The Washington Post is included in this report.