The Republican Party is enjoying a burst of raw enthusiasm among rank-and-file conservatives that has shot some relatively little-known candidates straight into the national spotlight — stirring concern among party leaders about how well some of them will fare with the broader electorate in November.

In North Carolina, national party officials make no secret of their displeasure at the possibility of the GOP banner being carried by a “tea-party"-backed candidate with an apparent history of religious zealotry and drug use. In divorce records, the man’s ex-wife said he planned to raise his stepfather from the dead in New Jersey.

In South Carolina, the tea party favorite for governor is trying to bat down accusations of infidelity.

In Nevada, a leading conservative contender is facing questions about her ties to the Church of Scientology.

And the newest hero of the tea party movement, Rand Paul, who won the GOP Senate primary in Kentucky, startled more-mainstream Republicans by questioning part of the historic 1964 Civil Rights Act that allowed the government to force lunch counters to desegregate.

Of these disparate candidates, some are truly outsiders; others are fairly experienced politicians getting their first real shot in the searing spotlight of national politics.

And though their potential problems are quite different, they have at least two things in common: They have not undergone the testing and vetting that candidates traditionally face. And they are making some Republicans nervous about whether they will be able to beat their Democratic opponents in the fall.

“Nonpoliticians are being given an increased level of credibility,” said Nathan Gonzales, political editor for the nonpartisan Rothenberg Political Report. “A consequence of not being a politician is never having been a candidate before, never being in the spotlight and never facing the media.”

To be sure, plenty of candidates backed by the movement have political experience and broad appeal, perhaps most notably Marco Rubio, the Senate candidate and former speaker of the state House of Representatives in Florida who pushed Gov. Charlie Crist from the Republican primary. Crist is now running as an independent.

Some in the movement also have shown a pragmatic streak, particularly in aligning themselves behind moderate Sen. Scott Brown in Massachusetts.

But the tea party movement has not yet elected one of its own in a general election for federal office, so it’s unclear how strongly its candidates will appeal beyond the party’s base.

“This isn’t a college debate about who made the best points,” said Republican strategist David Winston, who has seen tea party candidates rising as they focus their arguments on deficit spending and federal overreach. “If they’re going to win races, they have to prove they can build a coalition.”

In most districts, that means attracting independent voters. And polls show that the swing of independents toward the GOP has created the party’s widespread optimism about taking control of the House.

But it has also made some question the political viability of the tea party’s small-government rhetoric, heated critiques of the administration and uncompromising stance on immigration.

In at least a few cases, movement enthusiasm has embraced candidates with personal and other problems that may make them unacceptable to voters in November.

The clash between primary and general election rhetoric went national recently, when Paul publicly questioned the federal government’s role in ending racial segregation in private businesses.

Paul’s comments were in line with his libertarian views, but made little political sense to many Republican strategists. Paul later said he would have voted for the legislation.

In Nevada, Democrats are casting former Assemblywoman Sharron Angle as another Paul. Angle, who has been endorsed by a national tea party group, has been surging in the Republican Senate primary, where a lineup of candidates is vying to take on Senate Majority Leader Harry Reid.

Last week, the Las Vegas Sun found her campaign removing from her website references to famous Scientologists after it emerged that she once pushed for a prison rehabilitation program, modeled on the teachings of church founder L. Ron Hubbard, that aimed to treat drug addiction with saunas, massages, organic foods and a vitamin regimen.

Angle’s campaign said the timing was a coincidence.

Her opponent, Sue Lowden, has jumped on the Scientology controversy in a campaign ad showing prisoners in orange jumpsuits receiving spa treatments. A framed picture of actor and Scientologist Tom Cruise sits nearby.

Polls show Angle leading Lowden, the GOP establishment’s preferred candidate, who has had her own troubles with holding unusual positions on political issues. Lowden drew a wave of criticism and poultry puns when she spoke nostalgically about a time when people bartered with chickens for healthcare.

Reid allies are rooting for an Angle win — and that has become Lowden’s primary message.

“If Sharron Angle wins, you will hear the champagne corks popping in Reid’s office all the way in Nevada,” said Lowden campaign manager Robert Uithoven.

While national Republicans have avoided meddling publicly in Nevada, they haven’t shown the same restraint in North Carolina’s 8th Congressional District.

Party officials spoke out against political newcomer Tim D’Annunzio, who has fought his way through a Republican primary and is now in a runoff with the Republican establishment candidate. After sitting on the sidelines as D’Annunzio attracted tea party support and spent $1 million of his own money, the party felt it could no longer be quiet about his history.

Divorce papers show that D’Annunzio’s ex-wife said he was delusional and since a religious conversion believed he was the Messiah. The 15-year-old records also show a history of drug use. D’Annunzio has acknowledged drug use in his past and has described himself as reformed.

“What we have in this runoff is two conservatives, and one of them is a well-liked former sportscaster and the other one is a guy with a very troubling criminal background that the Democrats would be all too happy to exploit in the fall,” said Andy Sere, spokesman for the National Republican Congressional Committee.

Careful not to offend the candidate’s supporters, he added, “I think we’ve been clear from the outset that our issue has everything to do with electability and nothing to do with ideology.”

A handful of tea party leaders in the district have since distanced themselves from D’Annunzio’s campaign.

In South Carolina, tea party groups appear to be sticking by Nikki Haley, who is embroiled in a far more familiar political scandal. A blogger and former political aide to Gov. Mark Sanford said last week that he’d had an affair with the married state lawmaker. Haley denies it, as well as a second allegation from a lobbyist.

Her strongest backers have defended her.

“The establishment is very scared and is known for dirty tricks. This is a way to bring her down. I don’t believe it,” said Colen Lindell, founder of the Aiken County Tea Party, who then acknowledged he worried that the allegation might doom Haley if she becomes the nominee.

“I would much rather have a Republican in office than not,” he said.

kathleen.hennessey@latimes.com