PORTLAND — Democratic U.S. Rep Mike Michaud ended speculation about his run for governor Wednesday when his campaign confirmed that he’s entering the campaign with a formal announcement Thursday in Lewiston.

The five-term congressman, who has said he wants to restore civility to the Maine State House, has been raising money to challenge Republican Gov. Paul LePage, who’s seeking re-election. Also in the race is independent Eliot Cutler, who lost a close race to LePage in 2010.

Michaud had no comment Wednesday, saving his remarks for a noon rally Thursday at the Franco-American Heritage Center in Lewiston, a Democratic stronghold.

The formal announcement sets up a three-way race between Cutler, LePage and a Democrat, the same scenario that propelled LePage to victory in the last election.

First, Michaud faces a primary challenge from Steve Woods, a Democratic businessman and Town Council chairman in Yarmouth.

Though he isn’t a smooth-talking politician, Michaud will be a formidable candidate because he’s a moderate Democrat with working-class roots and union support, said Sandy Maisel, a political science professor at Colby College.

“He is not charismatic. He’s not terribly articulate. But one-on-one, and in small groups, he’s very persuasive and people take him to be real,” Maisel said. “People are looking for politicians who’re real.”

LePage’s campaign insisted he’s in the driver’s seat, with a lead in internal polls.

“People appreciate that under his administration joblessness has gone down, thousands of jobs have been created, and he’s fixing long-term debt and budget problems that have existed for years,” said Brent Littlefield, the governor’s senior political adviser.

Woods, who also wants to challenge LePage, said he welcomed Michaud to “a campaign process where I believe thoughtful solutions, positive collaboration and true statesmanship will prevail to the benefit of all Mainers.”

When Michaud announced his exploratory committee, he made the comment about restoring civility at the State House, a veiled reference to the blunt-spoken LePage.

LePage has often made news for gaffes or missteps, the latest when he used a sexually vulgar phrase in June to describe how he believed a Democratic lawmaker was taking advantage of the people.

But that doesn’t seem to matter to LePage’s base of supporters.

Though some moderate Republicans may support the other candidates, the governor can expect to win at least a third of the vote based on his core conservative supporters regardless of what he says or does between now and the election, said Mark Brewer, a political science professor at the University of Maine,

That’s important in a three-way race, he said.

“Some Republicans may desert him and go to Cutler or Michaud,” Maisel said. “But one thing that we learned four years ago is that you don’t underestimate Paul LePage.”