And their doing so isn't quite as strange as it might seem at first glance.

Republican Santorum and Democrat Wofford, both former senators now, are to serve as state cochairs of ONE Vote '08, which is seeking to raise issues of extreme poverty and global disease during the presidential campaign.

A formal announcement is scheduled in Harrisburg today. The group is an offshoot of ONE, which was founded by Bono, the Irish rock star.

In creating an organization in Pennsylvania, the people at ONE turned initially to Santorum, 50, a longtime ally who, as a senator, fought for projects to combat global AIDS. Bono once admiringly described him as "a defender of the most vulnerable."

Santorum, in turn, suggested Wofford, 82, as the logical Democrat to cochair a nonpartisan effort. Since their 1994 race, which Santorum won, the two men have worked together on such topics as faith-based community initiatives and national service.

"As a politician, I think you have an obligation to show the public that you fight on the issues and that it's not personal," said Santorum, who served in the Senate until losing to Democrat Bob Casey in 2006. "To prove it, you should go out of your way to work together on issues that you both care about."

John McCain and Barack Obama already have made commitments to build on the efforts of the Bush administration to combat AIDS and malaria in poor countries - and to visiting Africa during a first term.

In Wofford's view, that doesn't eliminate the need for continued political pressure.

"When there is common ground between the candidates on a good issue like this," he said, "it's very important that it not be relegated to the periphery just because it's not controversial."

The group would like to hear more specifics from McCain and Obama and is hoping that people like Santorum and Wofford can help.

"We want them to talk to their friends, to the press, and to the campaigns directly about why this is important," said Taylor Royle, a spokeswoman for ONE Vote '08. "We want them to talk in public and behind the scenes."

Nationally, the effort is chaired by two former Senate majority leaders, Republican Bill Frist of Tennessee and Democrat Tom Daschle of South Dakota.

Wofford was an early and avid supporter of Obama. Santorum initially opposed McCain's candidacy, backing him only after he became the GOP's presumptive nominee.