The former first couple and the best known and most powerful Democrats for nearly two decades - Bill and Hillary Clinton – will be taking the stage Sunday at a campaign rally, to launch an active campaign for their former opponent Barack Obama. Though Obama defeated Hillary Clinton in a Democratic primary contest, the Clintons are, of late, getting used to their new role: ‘cheerleaders’ for Obama, as they campaign in earnest for the Democratic ticket.

The former president and the New York senator will appear with Joe Biden, at the rally in Scranton, a working class town that has assumed a massive role in the 2008 presidential race. Both Biden and Hillary Clinton have emphasized their Scranton roots to illustrate their connection to blue collar voters. Biden was born in Scranton and lived there for several years as a child, while Hillary Clinton’s father grew up in the town and is buried there.

Hillary Clinton is also scheduled to hold a fundraiser for Obama on Sunday night in Philadelphia, and a rally on Monday in the Philadelphia suburb, Montgomery County, which is rich in swing voters. Clinton trounced Obama by 10 points in Pennsylvania primary, mostly due to her strength among white working class voters. Though McCain has campaigned actively in Pennsylvania, recent polls show Obama opening up a comfortable lead.

In the next few days, Hillary Clinton also planned return visits to Ohio and Florida, and has scheduled trips to Omaha, Nebraska, and Minnesota.

Aides said Hillary Clinton has been remarkable in her role of an Obama cheerleader, despite the bitter primary in which she raised questions about his electability and readiness to govern. It is also said that her long and often bumpy career in public life has taught her to compartmentalize her feelings, and by nature she does not dwell on the past.

Bill Clinton, on the other hand, appeared to have taken his wife’s loss at the primaries more personally. However, he gave Obama his full-throated endorsement at the Democratic convention in August. Only recently has he begun stumping for the Illinois senator by appearing at fundraisers and headlining two major events in Florida earlier this month.

After the Sunday rally, the Clintons will follow separate itineraries through presidential battleground states. They will also campaign on behalf of Democratic House and Senate candidates across the country.