In 2010, no one saw them coming. In 2012, they were beaten back by running to the right. In 2014, the question may be: do they matter anymore?
Such is the evolving role of tea party candidates in recent Republican primaries, where incumbent GOP candidates continue to tread carefully with challenges from their right flank.
For Senate Minority Leader Mitch McConnell of Kentucky, much lies in the balance as (once again) his party is poised to take over the body and make him majority leader – that is as long as he wins his 2014 re-election campaign. McConnell's prospects got bit murkier now that he not only faces a credible general election opponent in Democrat Alison Lundergan Grimes, but also a potentially well-funded primary challenger on the right in Matt Bevin.
Bevin, a wealthy businessman and political neophyte born in New Hampshire, has all the right tea party moves on the surface – he talks about the importance of acting on principle over compromise, the dangers of becoming a creature of Washington, D.C., and he's anti- virtually everything.
He also recently picked up the endorsement of the Madison Project, a conservative group that helped Sen. Ted Cruz, R-Texas, defeat his establishment GOP opponent in 2012.
"We're tired of the bail outs, we're tired of the amnesty, we're tired of the votes against our 2nd Amendment rights, we're tired of the votes that repeatedly allow the federal government to spy on law-abiding citizens, we're tired of the pay increases for yourself," Bevin says in an interview with U.S. News. "We're just tired of it."
McConnell, Bevin adds, isn't doing much for Kentuckians or conservative principles.
"He's interested in Mitch McConnell and not in the people of Kentucky," Bevin says of the 30-year Senate veteran. "He constantly brags how he'd like to be the Senate majority leader, but he's not even doing a very effective or good job as the minority leader and the people of Kentucky are saying, 'what about us?' "
Despite only pulling in 20 percent of Republicans in a recent poll, a defiant Bevin claims Grimes is poised to win the seat for Democrats if McConnell is the GOP option.
"There's one Republican in Kentucky who could lose this seat for the Republican Party and that's the guy who's in it," he says, noting McConnell's 37 percent approval rating, the lowest of any sitting senator.
But even though Kentucky is the state where anti-establishment, tea party-backed newcomer Rand Paul was able to knock off McConnell's hand-picked heir to the open Senate seat in 2010's raucous primary, there are signs that Bevin won't be up to repeating the feat. Paul, who's father former Rep. Ron Paul of Texas is a conservative cult hero, was aided by his father's nationwide network of libertarian-minded donors and rode the cresting tea party wave to the finish line.
But that same anti-establishment Paul has now turned a corner and is backing McConnell for re-election, despite differing with him on several major issues in the Senate.
"I just don't see how someone with no name [identification], who is 39 points down makes that up," says John McCarthy, a former Kentucky Republican Party chairman, who backs McConnell. "Matt Bevin would have to spend every nickel he personally owns to be able to catch up."
McConnell, meanwhile, in addition to picking up Paul's endorsement which carries weight with key conservatives, has raised more than $13 million so far for his re-election bid.
Bevin brushes back the Paul endorsement, saying he supports his positions but hints the senator's potential presidential ambitions are impacting his pick in the race.
"I like how he votes, I like what he stands for as a conservative, he's a true conservative who actually votes as he talks and actually takes action; those things I admire in him," Bevin says. "But Rand has, I think, other things on his on his potential horizon and he's trying to be as strategic as he can be in making decisions that are in those interests."
Correction 8/8/13: This story has been updated to correct a transcription error – an extra ‘is’ originally appeared in a quote from Steve Voss.