Utah tea party supporters united in May to achieve one goal: defeat three-term U.S. Sen. Bob Bennett at the Republican state convention.

They succeeded in that, but settling on his successor has proved harder.

Illustrating how fractured the tea party movement is in Utah, one of the founders of the state's tea party movement, David Kirkham, endorsed front-runner Tim Bridgewater on Monday. Attorney Mike Lee, 38, had already picked up the support of the California-based Tea Party Express, which is weighing in on primary races nationwide.

A lot is at stake. Whoever wins Tuesday's GOP nomination should cruise to victory in November in heavily Republican Utah. A Democrat hasn't won a U.S. Senate race here since 1970.

The marquee race Tuesday is the runoff for the Republican gubernatorial nomination in South Carolina. State lawmaker Nikki Haley has shrugged off accusations of infidelity and questions about her religion _ an Indian-American, she was raised a Sikh and baptized a Methodist _ to emerge as the odds-on favorite to become the state's first female governor. Haley almost won the state primary outright with 49 percent of the vote, but because she didn't get more than half she faces a runoff against Rep. Gresham Barrett.

Six-term Rep. Bob Inglis is struggling to hold onto his House seat in a GOP runoff against prosecutor Trey Gowdy. Elsewhere in the state, Tim Scott, a black state lawmaker, faces Paul Thurmond, the son of former segregationist Strom Thurmond, for the Republican nomination in a race that could provide a measure of both racial progress in the South and the GOP's ability to diversify.

In North Carolina, Secretary of State Elaine Marshall is locked in a close runoff against Cal Cunningham, the favorite of Democratic Party leaders in Washington, for the party nod for the Senate. The winner faces an uphill race against Republican Sen. Richard Burr.

Mississippi also has a runoff for the Republican nominee in a House race.

Back in Utah, Bridgewater and Lee advanced to the primary on promises to rein in federal spending. But without an incumbent in the race and little to distinguish their platforms, tea party supporters have struggled to coalesce around a single candidate.

"We were very happy when the results of the nominating convention came out, but the purpose of all our involvement isn't necessarily to knock out the worst people, but to put in the best people who represent our values _ and that's Mike Lee," said Bryan Shroyer, political director for the Tea Party Express.

Federal Election Commission reports show the group has spent $30,000 supporting Lee since Thursday, mostly on radio advertisements.

At the convention, Bridgewater won 57 percent of the vote _ 3 percent more and he would have won the nomination outright. A Brigham Young University survey of convention delegates showed that 85 percent of delegates had a favorable impression of the tea party movement and 42 percent of delegates considered themselves active supporters of the movement.

Kirkham said he believes Lee and Bridgewater, 49, both qualify as tea party candidates and that either one would make a good senator, but he believes Bridgewater could get more done in Washington.

"They both go for the same principles. They pretty much believe the same things. It's just a matter of preference, a matter of personality," he said. "I think he'll work hard to form coalitions, to make sure that Utah's interests are taken care of back east."

The race between Lee and Bridgewater, the founder of a consulting firm specializing in emerging markets, has largely focused on their professional backgrounds.

Lee contends that as a constitutional scholar who once clerked for Supreme Court Justice Samuel Alito, he's better suited to limit the role of government to what the country's founders intended it to be. Bridgewater contends that his business background means he's better suited to help create jobs.

Also on Tuesday, Democrats will choose their nominee in the 2nd Congressional District. U.S. Rep. Jim Matheson is seeking a sixth term, but is facing a challenge from his left by retired teacher Claudia Wright.

Wright won 45 percent of the vote at the Democratic convention, forcing Matheson into his first-ever Democratic primary. Matheson is being targeted by the left for voting against President Barack Obama's health care bill. Matheson has since said he would oppose repealing the legislation.