* Economic focus of debate could limit scandal discussion
* Romney tries to consolidate support in Michigan debate
* With Cain reeling, others hope to make a splash
ROCHESTER, Mich., Nov 9 (Reuters) - Republican Herman Cain will try to move past an escalating sexual harassment controversy on Wednesday during a U.S. presidential debate on economic issues held in the hard-hit manufacturing state of Michigan.
The debate will be a homecoming for Cain's rival Mitt Romney, who was born in Michigan and hopes to consolidate his status as the candidate to beat in the Republican race to choose a 2012 challenger to President Barack Obama.
The economic focus is likely to limit discussion of the harassment allegations by four women against Cain, which threaten to derail the former pizza executive's White House campaign despite his denials.
But the controversy, which has lingered for more than a week, will be hard for voters to forget. Polls show it has eroded favorable voter perceptions of Cain without knocking him from his spot near the top of the pack with Romney so far.
"This debate is going to be about Herman Cain even if nothing is said about the harassment allegations all night," Republican strategist Ford O'Connell said.
Cain's difficulties could open the door for one of the other candidates battling for the allegiance of conservatives in hopes of becoming the clear alternative to the more moderate Romney in the Republican race.
"The whole Cain saga creates a real opportunity for one of the other anti-Romney candidates, someone like Newt Gingrich or Rick Perry, to shine," O'Connell said.
So far conservatives have failed to coalesce around a single candidate. A series of conservative contenders -- first U.S. congresswoman Michele Bachmann, then Perry and now Cain -- has risen in polls to challenge Romney, only to fall back.
Gingrich, the former U.S. House of Representatives speaker, hopes to be the next to make a run. He has seen his poll numbers inch up after several strong debate performances. A USA Today/Gallup survey on Tuesday put him in third place with 12 percent support, up 5 percentage points in a month.
Republican Senator Lamar Alexander said Gingrich might have been underestimated early in the campaign.
"He's a very talented person. It may be he's just so familiar to everybody that he wasn't taken seriously," Alexander told a Reuters Washington Summit. "With intense media coverage today, anything can happen. And it can happen almost overnight."
Perry, the Texas governor, was just behind Gingrich in fourth place but has started to air campaign commercials in states with early nominating contests.
ROMNEY SUPPORT STEADY
Support for Romney, the former Massachusetts governor, has held relatively steady in the mid-20s in polls for much of the year.
Eight candidates will participate in the 8 p.m. EST/0100 GMT debate at Oakland University in Rochester, Michigan, outside Detroit.
The economic struggles in the state, which has seen its manufacturing base hit hard by the economic downturn, will serve as a backdrop to the debate. The state unemployment rate of 11.1 percent in Michigan is the third-highest in the country and well above the 9 percent national rate.
Romney, whose father was a former Michigan governor and a former auto executive, is likely to be in the hot seat again as the rest of the Republican field races to catch up.
"Realistically, Romney is going to be a target, especially given the fact he is from Michigan and continues to be perceived as the guy to beat by a lot of folks," said Saul Anuzis, a former Michigan state party chairman and a Romney supporter.
Democrats got the ball rolling on Tuesday with an attack on Romney for opposing the 2009 auto industry bailout that helped revive Michigan-based General Motors and Chrysler. The web video featured a Romney column written in 2008 titled "Let Detroit Go Bankrupt."
Democrats hope the issue will be a potent one for Obama if he meets Romney in a 2012 general election match.
With the Republican campaign consumed for more than a week by the Cain scandal, Anuzis said he expected a concerted effort to focus on economic issues like the flat tax plans from Cain and Perry and to stay away from the Cain controversy.
"I think there will be pressure to ensure they stay on the issues and there is some substance to it," Anuzis said.