Missouri businessman John Brunner (R) announced his bid Monday to take on Sen. Claire McCaskill (D), roiling the waters of a key race with national implications.

Brunner, chairman of pharmaceutical and personal care products company Vi-Jon, is likely to be at least a partial self-funder and joins a Republican primary field with no clear frontrunner. His two opponents are six-term Rep. Todd Akin and former state Treasurer Sarah Steelman.

“This completely changes the race,” said Republican consultant Jeff Roe, who is based in Kansas City and isn’t affiliated with any Senate candidate. “Missouri’s never had a self-funder like this at a high-level office.”

In his announcement, Brunner positioned himself as a Washington, D.C., outsider.

“I came to realize, like many of you, that career politicians with political experience alone are unable to restore the American dream. They have no answers and have lost their way because they have no real world experience to guide them,” the ex-Marine said in his announcement speech.

In a political climate that is virulently anti-Washington, his outsider status could be a decided advantage. But tested politicians have advantages, too: People know who they are, and they know how to campaign.

“Brunner is going to get a lot of establishment support,” said a Republican with a deep knowledge of Missouri politics. “The party regulars have looked to him and hoped that he would run. There’s a fear that Akin and Steelman, that neither of them are ready for prime time.”

But, of course, it’s also unclear whether Brunner is ready for the rigors of a statewide campaign.

“John Brunner is untested,” said Missouri-based GOP consultant James Harris, who is also not affiliated with any Missouri Senate campaign. He noted that wealthy self-funders did not do well during the last cycle.

He said a key early hurdle for Brunner will be introducing himself to enough primary voters before the primary contest on Aug. 7. The two largest regions with a heavy concentration of GOP primary voters are the St. Louis media market, which has a bit less than a third of all GOP voters in the state, and the Springfield market, which has a little more than a quarter of those voters, Harris said.

“Akin has about 75 percent name ID in the St. Louis market — he’s pretty well-known,” Harris said. Steelman has some name recognition from her time running for statewide office, he said, and she also has a strong presence in southwest Missouri.

“For Brunner, the challenge is: Where do you go to get the votes?” Harris said. “No one knows John Brunner.”

Roe noted that with early television advertising buys, Brunner could likely catch up on name identification with Steelman and Akin among likely GOP primary voters.

But gaining name ID is only one part of Brunner’s challenge.

“Whether he will be a retail politician will be the deciding factor of his electability because Todd Akin and Sarah Steelman — much more than speaking to crowds of 500 people — they are retail politicians,” Roe said.

Harris agreed that person-to-person politics would be key. “You look at some of our most successful politicians — people like Kit Bond, John Ashcroft and Roy Blunt — they’ve all excelled at retail politics,” he said.

And beyond mastering the art of campaigning, he’ll face the increased scrutiny that comes with a high-profile campaign for a competitive seat.

Only hours after the Brunner announcement, Akin’s campaign manager pushed back against the idea that the businessman could take the mantle of an outsider.

“Congressman Akin has always been the outsider in Washington. The Congressman has been fighting the establishment and has the votes to back it up,” Karl Hansen said. “If Mr. Brunner is looking for an outsider in the race, he should cast his ballot for Rep. Akin.”

Akin, a staunch conservative who has positioned himself as such in the race, has been working at events across the state to build connections with new voters. While he has strong connections in the St. Louis area, near his Congressional district, he is less well-known statewide.

Steelman has struggled to gain momentum in her campaign, experiencing staff turnover and racking up an unenviable burn rate during the first two quarters of the year. According to Federal Election Commission records, she raised $387,000 from January to June but spent $395,000.

But she might end up with a gender and geographic edge. Brunner and Akin will likely have their strongest base of support in St. Louis, while she could pull strong numbers elsewhere in the state, including in central and southwest regions of Missouri. And some strategists think Steelman, as a woman, could make a case that she would have an edge in taking on McCaskill. Her campaign aides stress that a three-way race is a huge boost to Steelman’s candidacy.

Third-quarter fundraising reports from Steelman and Akin, to be released later this month, will help illuminate where their campaigns stand.

Brunner has brought on well-known consultants for polling and media. Randall Gutermuth and Linda DiVall of American Viewpoint are very familiar with the terrain of the Show Me State and are leading his polling operation. Paul Curcio of SRCP Media is heading Brunner’s media operation.

All of this does little to change the re-election challenge for McCaskill.

Democratic strategist Mike Kelley, a former executive director of the state party, said Brunner’s entry doesn’t change the dynamics of the Senate race.

“I don’t think this changes the outlook for Claire much,” he said. Perhaps telegraphing Democratic attacks, he said Brunner and Akin represent the “extremists” wing of the GOP that is “out of touch with mainstream Missouri.” And he slammed Steelman as a “perennial candidate.”

Roll Call rates this race as a Tossup.