WASHINGTON - Emerging from a downtown office building this week after a seminal speech on conservative values, U.S. Rep. Michele Bachmann stepped into one of her campaign's newest forms of conveyance, a plain red extended-cab pickup truck.

Holding the door open was Brett O'Donnell, her principal speechwriter, debate coach, message guru, and all-around errand guy. With Bachmann and two other top aides inside, O'Donnell swung the door shut, hopped behind the wheel and drove away.

Next stop? South Carolina. Iowa after that. But if Bachmann has seemed a little down on her luck lately, O'Donnell, who has emerged as her campaign's leading evangelical light, is keeping the competitive juices flowing.

"The cement is still very wet in this election," O'Donnell said in an interview amid the furor of the sexual harassment allegations against Herman Cain, the latest in a succession of GOP front-runners that once included Bachmann.

With a highly unsettled election foremost on his mind, O'Donnell is not giving up, even if it means he sometimes has to chauffeur the candidate around the capital in his own Chevy truck.

It wasn't always like this for O'Donnell. Entering politics at the invitation of Karl Rove, who brought him on as President George W. Bush's debate coach in 2004, O'Donnell went on to assume the same role in Sen. John McCain's 2008 presidential campaign.

Before that, he was principally known as a nationally renowned college debate coach from the late Jerry Falwell's Liberty University in Virginia, where O'Donnell studied during the Reagan years.

Debate coach is now O'Donnell's title in the Bachmann campaign, which got its initial jolt from a well-received debate performance last June in New Hampshire. But even in a year where multiple debates have largely shaped the ebb and flow of the GOP race, this has hardly been the extent of O'Donnell's influence in her low-dollar political organization.

"I help with debate prep, speechwriting, messaging and anything else she asks me to do," O'Donnell said moments before Bachmann's speech at the Family Research Council, while he quietly adjusted the microphone and placed the printed speech on the podium so Bachmann could make a hands-free entrance.

In ways large and small, O'Donnell is considered one of Bachmann's most trusted advisers, breaking through her tight family circle by dint of loyalty, hard work, and their common evangelical roots.

"He's a big part of the campaign," said national campaign manager Keith Nahigian, who took over after the departure of GOP heavyweight Ed Rollins. "Brett works every day, all day."

'On the bus'

In the Bachmann campaign, ex-staffers say you're either "on the bus" or off the bus. Her New Hampshire staff, feeling decidedly off the bus, quit en mass last month. O'Donnell, who once wanted to be a minister, is definitely on the bus, along with Nahigian and communications director Alice Stewart, who keeps the media at bay.

Campaign aides give O'Donnell credit for bringing message discipline to a campaign plagued by Bachmann's tendency to extemporize and make gaffes, one of the most damaging being her suggestion of a link between the HPV vaccine for girls and "mental retardation."

Rollins, who had already stepped down as campaign manager, left the campaign in frustration soon after that episode, giving a series of candid interviews that raised questions about Bachmann's viability and O'Donnell's political acumen.

It was O'Donnell, Rollins told the Star Tribune, who turned up the unknown woman who gave Bachmann the faulty vaccine story. Rollins gives O'Donnell high marks for writing speeches and crafting debate points, but not for campaign strategy.

"Brett doesn't know a lot about politics," Rollins said. "He's sort of her security blanket. ... She didn't want a strategy. She wanted a cheerleader, and he gives her that comfort zone."

Part of the comfort zone is prayer, according to Rollins: "They're together all the time. They share a common faith. He understands the language of the evangelical movement."

According to Nahigian, O'Donnell has helped keep the campaign on an even keel. "He brings consistency, the ability to stay on message, and consistently break new ground at the same time," he said.

O'Donnell acknowledges that his background as a championship debate coach is "not the normal path to politics."

The common thread is persuasion. "Mostly, it's about the way you frame and simplify arguments so they can be consumed," said Warren Decker, O'Donnell's mentor and rival as head debate coach at George Mason University in Virginia.

In the past, O'Donnell has rejected the image of the hired political gun, once referring to himself as an "ideologue" with a conservative agenda. He's also shown a willingness to play by the rules of the game. O'Donnell has been criticized in evangelical circles for allowing his college teams to argue both sides of each debate topic -- even abortion.

'On script'

One of the challenges facing O'Donnell is that while Bachmann's unguarded utterances often hatch mistakes, they also provide some of the most inspiring moments for her passionate social conservative supporters.

Following O'Donnell's script at the Family Research Council last week, Bachmann gave a rushed, 26-minute speech with her eyes mostly cast downward at a prepared text. The speech made news mostly for the epithet "frugal socialists" to describe some of her more centrist GOP rivals.

O'Donnell occupied his usual position in the back of the room, between Nahigian and Stewart, observing Bachmann's every movement and inflection.

Bachmann -- and by extension O'Donnell -- has been criticized recently for not offering anything new to her campaign, which has tended to stick to well-worn Tea Party themes of government overreach, runaway spending and repealing Obamacare.

O'Donnell isn't necessarily opposed to big, game-changing gestures. He was among the aides urging McCain to make a one-term pledge in 2008 to show his commitment to the nation and to jump-start his faltering campaign.

There are parallels there for Bachmann, who promises that she would press her conservative principles as president regardless of the electoral consequences. "It's not about getting elected to a second term," O'Donnell said.

But O'Donnell remains distrustful of grand gestures for the sake of getting attention.

"Gimmicks, whether in campaigning or governing, are bad," he said. "You have to be what you are."

Kevin Diaz is a correspondent in the Star Tribune Washington Bureau.