Rep. Michele Bachmann is mingling with Republican voters in this key primary state Wednesday, trying to capi­tal­ize on the momentum her upstart presidential campaign has built in recent weeks.

Bachmann plans to push hard in South Carolina, which holds the third nominating contest of the primary season. It is known as the state where many underdog candidates lose steam, including then-Arkansas Gov. Mike Huckabee, who four years ago appealed to the same evangelical constituency as Bachmann does this time around.

But the rise of the tea party here provides new opportunities for Bachmann, who is seeking to be the standard-bearer for the conservative grass-roots movement.

After formally launching her campaign in her birth city of Waterloo, Iowa, and stopping briefly in New Hampshire, the Minnesota congresswoman is conducting a bus tour of South Carolina that will focus on backyard chats and town hall meetings across the state. She began in this historic port city early Wednesday, and will end in Rock Hill, near the North Carolina border.

Bachmann unveiled the tour bus — emblazoned with her blue campaign logo, the ‘h’ of her last name embellished with a red-and-white swish — at a kitschy entertainment complex in Myrtle Beach on Tuesday night. The vehicle emitted a low honk as it approached hundreds of curious tourists and local Republican activists who had gathered to hear Bachmann speak.

Outside the Ripley’s Aquarium, steps from a mock volcano spitting bursts of fire, Bachmann unleashed a string of her characteristically acerbic one-liners about President Obama, liberals and big government.

“I think we should take some of the obesity programs coming out of the White House and apply it to Washington!” she said as the crowd roared.

In an issue that has galvanized Republicans nationally, Bachmann voiced support for Boeing, which is the subject of a National Labor Relations Board complaint for moving a plant from Washington state to South Carolina, a state that is less supportive toward unions. She repeated her promises to cut taxes, reduce governmental regulation and repeal the health-care overhaul.

“These people in Washington, D.C. They don’t really care what you think,” she told the crowd. “They care what they want. But we want something too. We want to have a change in Washington and we’re going to get it in 2012.”

Many in the audience said they were undecided in the race for the GOP presidential nomination, eager first and foremost to see Obama defeated and unsure of which Republican hopeful was best positioned to viably challenge him. That didn’t stop them, however, from scooping up Bachmann bumper stickers and lapel pins that read, “Give ’em hell, Michele.”

“She seems to speak in a very common-sense manner. She doesn’t sound like a politician,” said Carlo Gamboni, 63, a retired builder and developer who is also considering giving his support to Texas Gov. Rick Perry, should Perry enter the race.

As she has at so many of her recent appearances, Bachmann closed her remarks Tuesday night to the strains of “American Girl” by Tom Petty. According to NBC, the singer and songwriter is demanding that she stop using his song on the campaign trail.