— When South Carolina Gov. Nikki Haley made a surprise appearance here Thursday evening on the stage of a town hall featuring Republican presidential contender Michele Bachmann, the crowd erupted with a level of glee that Bachmann’s competitors could only dream about.

Haley has not endorsed anyone in the still wide-open Republican field. But her rock-star status among conservative Republicans and tea party supporters in South Carolina has prompted a clamor by presidential contenders to win her support. And Haley’s recent announcement that she likely will endorse someone by the end of the year means that clamor will not die down soon in a state that has given a victory to the eventual nominee in every one of its GOP presidential primaries since 1980.

Former Massachusetts governor Mitt Romney campaigned for Haley last year, when she shocked the political establishment by winning the Republican nomination for governor against an establishment foe. Jon Huntsman, the former ambassador to China, paid Haley a visit in May. Texas Gov. Rick Perry reveled in her praise a few weeks ago, when Haley said during his kickoff tour through the state that “he has a great hope for America.”

But Bachmann may have hit the jackpot Thursday when she appeared with Rep. Tim Scott (R-S.C.) in his home town for the second in his series of presidential town halls. With a sound system blaring the Elvis Presley tunes that have come to characterize her well-choreographed political events, Bachmann strode onto the stage at Trident Technical College to an exuberant crowd of more than 300.

Even before Haley showed up, Bachmann brought the crowd to its feet more than once as she laid out her reasons for wanting to be president of the United States: to end — and reverse — the policies of President Obama.

Bachmann’s popularity among tea party conservatives was on full display as she promised to repeal the health-care overhaul law and the Dodd-Frank Wall Street reform law, to strip the Environmental Protection Agency of its regulatory power and to rein in federal spending. With a zeal that elicited shouts of agreement from the crowd, Bachmann exclaimed that the 2012 election is conservatives’ only window of opportunity to “take our country back.”

When Scott, who chose questions submitted by audience members and read them aloud to Bachmann, said that his next question would come from “an undecided voter named Nikki,” the energy in the room spiked higher. Haley walked onstage and into Bachmann’s open arms — and asked the candidate a softball question about the National Labor Relations Board’s controversial suit against Boeing over its efforts to move 1,000 jobs from Washington, a union state, to right-to-work South Carolina.

“It’s the most unAmerican thing I’ve ever seen,” Haley said.

The question highlighted an issue that helped forge Haley’s reputation as a limited-government champion among conservative Republicans — and it gave Bachmann an easy opportunity to share that space and shower her questioner with buckets of praise.

“First of all, as president of the United States, I would take your phone call when you call me,” Bachmann said, alluding to Haley’s frequent barbs at the Obama Administration for not responding to her inquiries (Haley grinned and gave the audience an enthusiastic thumbs up).

“Some of you may not know this,” Bachmann continued, “but Governor Haley is a very active governor working on your behalf, and she tried desperately to get the attention of the administration not only just on Boeing but also on health care and also dealing with the issue of illegal immigration. Governor Haley is now at the point where she has to hold a press conference to shame the White House to take her phone call!”

The crowd loved it. “She’s so exciting!” said Sheri Irwin, 47, an unemployed wedding photographer from Charleston who views immigration reform as a key issue in her choice of nominee. “If we don’t do something, we’re going to lose this country. Michele knows what she’s talking about. She doesn’t need notes. She doesn’t need a teleprompter.”

An adviser to Scott said after the town hall that it would be a mistake to read too much into Haley’s appearance, since she has made clear that she won’t endorse anyone until all the candidates have had a chance to visit South Carolina and make their cases to Republican voters. The governor happened to be in Charleston for another event, so it was not a difficult appearance to arrange, the Scott adviser said.

Still, Haley adviser Tim Pearson said that Haley “was thrilled” to stop by when Scott asked her to do so. He also said that Bachmann stayed with Haley at the governor’s mansion this year — but he noted that Haley has invited other presidential contenders to do so, as well, and Bachmann is the first to take the governor up on the offer.

“She thinks we have a great slate,” Pearson said, “and will endorse someone towards the end of the year. She hasn’t made a decision as to who yet.”

Haley is a rare Republican politician who excites tea party activists with her limited-government stands as well as party leaders who admire her political skill — and her cachet not only as a woman but as an Indian American in a party long criticized for its poor outreach to minorities.

Scott, too, has gained a high profile as one of the few tea party-supporting African American politicians in the country. Both politicians have been able to criticize Obama without attracting accusations of racism that have popped up elsewhere within the tea party, and Haley in particular has used her status as the daughter of immigrants to speak forcefully about the need to stanch the flow of illegal immigrants into the country.

Scott hosted Huntsman at his one previous presidential town hall, and he said Thursday that he expects at least two more to be announced soon. He took an indirect shot at Romney, though, when a reporter asked him whether the candidate would struggle to win in South Carolina with so few trips here.

“I think you just answered your own question,” Scott said.