The couple, making their first dual campaign appearance for Senator Obama yesterday, dominated Democratic politics for a generation but now are supporting players, after reconciling themselves to Hillary Clinton's bitter nominating defeat.

''This election is too important to sit on the sidelines of history,'' Senator Clinton said, calling on her working-class and female supporters to take up the banner of her ex-rival.

''It took a Democratic president to clean up after the last president Bush'' it's going to take a Democratic president to clean up after this President Bush,'' she said in a working-class corner of swing state Pennsylvania.

''Make no mistake about it. We've done it before and we'll do it again. America will once again rise from the ashes of the Bushes.''

The Clintons teamed up with vice-presidential nominee Joe Biden, a native of Scranton and a man with working-class roots, just 23 days before the presidential election.

Senator Clinton told a crowd estimated at 6000, ''Barack Obama and Joe Biden are for you and that's why I am for Barack Obama and Joe Biden.''

President Clinton, still popular with rank-and-file Democrats, said Senator Biden and Senator Obama were better prepared than John McCain to pull the US out of the financial crisis. He called on his wife's supporters, in a state where she won a thumping 10-percentage-point victory over Senator Obama in the primary season, to look into their hearts.

''You need to remember, if you supported her, why you did it,'' he said, urging those who shared his wife's crusade for health-care reform and advocacy of the middle class to choose Senator Obama. ''If you ask yourselves who has the best ideas, who's got the best instinct, who's got the best ability to understand these challenges, who's got the best supporting cast, the answer is Barack Obama.

''That's why Hillary's here, that's why I'm here.''

Senator Biden paid tribute to both Clintons and portrayed himself and Senator Obama as the natural heirs to their political legacy.

Senator Clinton won a stunning 18million votes in her six-month nomination showdown and is set to play a vital role in the closing days of the election campaign.

Republicans had hoped simmering hostility towards Senator Obama from her supporters, especially white blue-collar voters in swing states, could provide an opening.

But the sudden depth of the financial crisis has boosted Senator Obama's ratings. Polls show that more voters trust him than Senator McCain to fix the economy a factor powering the Democrat's advantage in battleground states. AFP