WASHINGTON (AP) -- When Bill and Hillary Clinton take the stage Sunday at a campaign rally in Pennsylvania, it will be the launch of an active campaign for their former nemesis Barack Obama in the home stretch of the 2008 presidential race.
The nation's best known and most powerful Democrats for nearly two decades, the former first couple is getting used to a new role: cheerleaders for Obama, who vanquished Hillary Clinton last spring in a Democratic primary contest for the ages.
Whatever recriminations the Clintons may still harbor from that long battle seem to have been nudged aside as they campaign in earnest for the Democratic ticket.
The New York senator and the former president will appear with Obama's running mate, Joe Biden, at a rally Sunday in Scranton, a working class town that has assumed something of an outsize role in the presidential race.
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. Both Biden and Clinton have emphasized their Scranton roots to illustrate their connection to blue collar voters.
After the 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.
Bill Clinton, who worked tirelessly for his wife during the primaries, seemed to take her loss more personally. Nonetheless, he gave Obama his full-throated endorsement at the Democratic convention in August. But he began stumping for the Illinois senator only recently, appearing at fundraisers and headlining two major events in Florida earlier this month.
After the Scranton rally, the former president was headed to Richmond and Roanoke, Virginia. He also planned events in the next few days in Ohio and Nevada, battleground states he won in 1992 and again in 1996.
Hillary Clinton was scheduled to hold a fundraiser for Obama on Sunday night in Philadelphia and planned a rally for him Monday in Montgomery County, a Philadelphia suburb rich in swing voters.
Clinton trounced Obama by 10 points in last spring's Pennsylvania primary, largely due to her strength among white working class voters. Sensing opportunity, Republican John McCain has campaigned actively in Pennsylvania but recent polls show Obama opening up a comfortable lead.
Hillary Clinton also planned return visits to Ohio and Florida in the next few days and has scheduled trips to Omaha, Neb., and Minnesota.
She traveled Friday to Arkansas, her husband's home state and where she served 12 years as first lady, in hopes of making it more competitive for the Democratic ticket. A swing through Western battleground states is in the works as well.
Clinton did radio interviews this week in North Carolina, a reliably Republican state that has become a battleground in this presidential election. She also spoke to a Hispanic station in Florida and launched a women's canvass in Wisconsin Saturday by phone.
Aides said Hillary Clinton has been remarkably stoic about taking on the role of an Obama cheerleader following the close and often bitter primary in which she raised questions about his electability and readiness to govern.
Clinton's long and often bumpy career in public life has taught her to compartmentalize her feelings, her aides said, and by nature she does not dwell on the past.
In campaign appearances, she has pressed the need for a Democratic president to take on the nation's sour economy and crippling financial crisis. Polls during the Democratic primaries found voters gave her a clear edge over Obama when asked who would be a better economic steward.
"I think it is safe to say we have not seen more troubles at one time since World War Two," Clinton told a rally in Little Rock, Ark., Friday. "Probably no president will inherit more challenges that President Obama will, since Harry Truman had to take over from Franklin Roosevelt."
Aides said Clinton has headlined more than 50 events for Obama and has raised $10 million for his campaign since suspending her own presidential effort in June.
(This version CORRECTS Corrects one of Clinton visits will be Omaha, Neb., sted Iowa.)