Former presidents George H.W. Bush and Bill Clinton, who put politics aside to help raise more than $1 billion for disaster relief efforts, received the 2006 Liberty Medal on Thursday night.

"We honor them for answering the call of service again ... for rising above party and personal history to show the world what's best in the American spirit," said Joseph Torsella, president and CEO of the National Constitution Center.

The award annually honors an individual or organization that has "demonstrated leadership and vision in the pursuit of liberty of conscience or freedom from oppression, ignorance or deprivation."

Bush, a Republican, and Clinton, a Democrat, joined forces last year to aid Gulf Coast victims of Hurricane Katrina through the Bush-Clinton Katrina Fund. Earlier, they formed the Bush-Clinton Tsunami Partnership to help survivors of the December 2004 tsunami that killed more than 200,000 people in southeast Asia.

"A lot of people were surprised, to put it mildly, when President Clinton and I teamed up last year," Bush said, noting that his wife called them "the political odd couple."

But both presidents, in separate remarks, said that humanitarian efforts transcend partisan differences.

A tsunami survivor and a Katrina survivor presented them with medals at a ceremony at the National Constitution Center. The award comes with a $100,000 prize, which an event spokeswoman said would be donated to relief efforts.

This is the first Liberty Medal given under the auspices of the Constitution Center, a nonprofit organization founded in 2003 and dedicated to increasing public understanding of the Constitution.

The Liberty Medal, first awarded in 1989, was previously administered by regional civic groups including the Philadelphia Foundation and Greater Philadelphia First.

Past recipients include Polish union leaderLech Walesa, former President Jimmy Carter, former Supreme Court Justice Thurgood Marshall, South African leaders F.W. de Klerk and Nelson Mandela, former Secretary of State Colin Powell and, most recently, Ukrainian President Viktor Yushchenko.

Six recipients of the medal have subsequently won the Nobel Peace Prize.