Clinton urges supporters to rally around Obama

DENVER (Reuters) - Hillary Clinton urged her supporters on Monday to unite behind Barack Obama and said Democrats could not afford to let lingering frustrations from their nominating battle hurt Obama's bid for the White House.

Clinton, who lost to Obama in a bitter Democratic primary struggle, said the party would emerge united and energized from the nominating convention that opens on Monday -- but acknowledged it would not be easy.

"We are after all Democrats, so it may take awhile," the senator told a chanting, sign-waving crowd of delegates from her home state of New York. "We're not the fall-in-line party. We are diverse. But make no mistake, we are unified."

Democratic leaders have promoted party unity heading into the convention, hoping to head off a public rebellion from disgruntled Clinton supporters who have complained she was not treated fairly during the nominating fight.

Clinton has a prime-time speech on Tuesday night and her husband, former President Bill Clinton, speaks on Wednesday. She is expected to meet with her delegates on Wednesday to free them from their commitment to vote for her and urge them to back Obama.

She said the stakes were high in the November 4 presidential election and the country could not afford a win by Republican John McCain, saying he would follow in the footsteps of the unpopular President George W. Bush.

Polls show Obama running neck-and-neck with McCain, and some polls show about 1 of every 4 Clinton supporters have failed to fall in line behind Obama so far.

"I just want to make it absolutely clear -- we cannot afford four more years of President Bush's failed policies," she said. "I am looking forward to being at the White House when President Obama signs quality, affordable health care for every American."

The precedent-shattering primary battle between Clinton and Obama featured candidates striving to become, respectively, the first woman U.S. president and the first black U.S. president.

Clinton mocked a Republican advertisement using some of her criticisms of Obama during the nominating duel.

"I am Hillary Clinton and I do not approve that message," she said, earning a standing ovation from a New York crowd waving blue signs saying "Hillary Made History."

Clinton said the Democrats were like a family and the convention was a family reunion.

"We are united and we are together and we are determined," she said. "We're going to make sure that we win on November 4. So let's have a great convention."

(Editing by David Storey)