OLYMPIA, Wash. — Democrat Christine Gregoire, winner of one of the closest governor's races in U.S. history, was inaugurated Wednesday amid a legal challenge that could undo her election.

A roar of approval went up from fellow Democrats as Gregoire raised her hand and took the oath of office before a joint session of the Democrat-controlled Legislature.

Republicans, who had battled unsuccessfully to delay her inauguration, gave her a frosty reception. During her 45-minute speech, they mostly sat in stony silence, sitting during several standing ovations.

"This is not an easy time to lead," said Gregoire, a scrappy three-term attorney general who took on the tobacco industry. "Many have asked how I can govern without a clear mandate from the voters. I believe the voters have given all of us a mandate — a mandate to overcome our differences and to solve problems."

Backers of her Republican rival, Dino Rossi, continue to push for a whole new election to decide the race.

Rossi watched the ceremony on television at his "Rossi Revote Headquarters," and said, "Most people believe that Washington does not have a legitimately elected governor."

Although the state is dependably Democratic, Gregoire lost the first count in the Nov. 2 election by 261 votes and a machine recount by 42 votes. But she pulled ahead in a final hand recount ordered by Democrats, winning by just 129 votes out of 2.9 million ballots cast.

Ever since Rossi lost the hand recount, Republicans have said widespread irregularities, including votes cast by felons and dead people, spoiled the election to the point where it is impossible to truly know who won.

Republicans also contend that King County, a Democratic stronghold and the state's largest county, cannot match more than a thousand votes to actual voter names.

Invoking a rarely used law that allows an election "contest," Republicans have asked the courts to set aside the election and order a redo.

The case is expected to end up in the state Supreme Court.

Gregoire didn't apologize or acknowledge the continuing legal battle, but in a late insert to her prepared speech, she reached out to Rossi.

"Trust me, there is no one in the state of Washington who knows how grueling the campaign has been, and the two recounts, than my husband and our two daughters," Gregoire said. "So my heart goes out, my sincere appreciation and thanks, go out to Sen. Rossi and his family for all they have done and the personal commitment they have made on behalf of the citizens of the state of Washington."

Gregoire, 57, said the state is more unified than might be apparent from the disputed election. Voters everywhere want good-paying jobs, affordable health care, efficient government, good schools and a clean environment, she said. She also announced creation of a commission to look at election reform.

On the Net:

Legislature: http://www.leg.wa.gov

Governor: http://www.governor.wa.gov