LOS ANGELES - As she takes her place on the presidential debate stage again Wednesday, Michele Bachmann can no longer play the role of a frontrunner.

Despite being the big winner in the Iowa straw poll just weeks ago, slumping poll numbers and the weekend departure of her top two campaign strategists are raising fresh doubts even in the GOP about her ability to go the distance in a contentious Republican field.

Wednesday's nationally televised debate, at the Ronald Reagan Presidential Library in Simi Valley, now becomes a test of whether she can take on the two newly dominant figures in the race: former Massachusetts Gov. Mitt Romney and the man whose late entry into the race has deflated Bachmann's post-Iowa momentum and captured the hearts of many conservatives, Texas Gov. Rick Perry.

"This debate is really important for her because she got a little bit of momentum coming out of Iowa, but clearly that has dissipated," said Norman Ornstein, a congressional watcher with the American Enterprise Institute for Public Policy Research.

She has also faced staffing challenges. On Monday, Bachmann's campaign announced major changes in her organization. Ed Rollins, a veteran politico who brought gravitas to her campaign, stepped down as campaign manager, citing health reasons. But David Polyansky, a top Rollins aide who served as Bachmann's deputy campaign manager, also resigned.

Alice Stewart, Bachmann's campaign spokeswoman, said the campaign had entered a "restructuring phrase" and Rollins will continue to advise the campaign.

The congresswoman has a long history of sudden staff switches.

"No matter what level Michele is at, she has staff shake-ups," said Jack Tomczak, a conservative radio talk show host who worked as Bachmann's political director from 2008 to 2010. Over four years, Bachmann has run through six chiefs of staff, five press secretaries, five legislative directors and three communications directors, according to the Associated Press.

Staying power?

The history of staff changes, coupled with ex-staffers publicly and privately voicing doubts about Bachmann, adds to Republican questions about whether Bachmann has the staying power needed to muscle through an increasingly tough field.

Minnesota Republican Party Chairman Tony Sutton dismissed prognostications of doom that followed news of Rollins' new role.

"Every tremor is hyper-analyzed," Sutton said.

More changes may lie ahead.

In announcing Rollins' step back and strategist Keith Nahigian's assumption of campaign manager duties, Bachmann referenced Iowa three times. That may be a signal that she plans to double-down on her Iowa efforts.

A strong performance in an earlier New Hampshire debate and a solid win in the Aug. 13 Iowa straw poll gave Bachmann hefty credibility. But Perry's entry into the race the next day neatly stepped on her momentum and has left her fading even in the early-voting state. A recent poll showed Perry strongly leading Romney, with Bachmann far behind among likely caucusgoers. As Bachmann looks for traction, her priorities may shift. Bachmann has said she expects "a strong finish" in New Hampshire, which holds the first primary in the nation, but she has not campaigned in the state for weeks. She did campaign in Florida late last month and will return there next week.

She'll need to reignite her campaign to make headway in those early states. An NBC/Wall Street Journal poll released Tuesday showed Bachmann in fourth place, the first choice of just 8 percent of voters polled. Perry led the field with 38 percent, followed by Romney and U.S. Rep. Ron Paul, R-Texas. Bachmann's single-digit showing is similar to the numbers that ex-Gov. Tim Pawlenty, who suffered from poor fundraising on top of poor polling, got before he dropped out of the race.

"With the entry of Rick Perry, there is just not the opening there was for her," said Larry Sabato, director of the Center for Politics at the University of Virginia.

Sutton said the field is in flux and will start to level out in the next month or two. "Perry's numbers are artificially high and will even out," Sutton said.

A charismatic figure with long-tested right-of-center stances, Bachmann has shown herself a masterful politician against the odds before.

She manages to be on the "cutting edge" of what conservatives want to hear, Tomczak said, "before anyone else."

Bachmann's pitch for less government and less spending attracted Lori Thompson, of California's Redondo Beach, years ago.

"I think she's an impressive candidate," said Thompson, who donated $250 to Bachmann's campaign. But Thompson is not settled on Bachmann as her pick.

"I'm looking forward to the [Wednesday] debate," she said.

In her two presidential debates so far, Bachmann has shone. She won applause for announcing her candidacy at her first debate and successfully batted back Pawlenty's attacks in an Iowa debate last month.

On Wednesday, Bachmann will share a stage with Perry for the first time.

Bert Rockman, head of the political science department at Purdue University, said Bachmann will have to use the debate to "show what distinguishes her from Perry for her base."

Romney, a second-time presidential candidate, has the national debate experience Bachmann lacks and held frontrunner status before Perry jumped in.

But experienced Bachmann-watchers say the race isn't over.

"It would be a mistake for anyone to count her out," Tomczak said. But, he added, "she could also implode tomorrow."

Rachel E. Stassen-Berger • Twitter: @rachelsb Baird Helgeson • 651-222-1288