Joseph M. Torsella's decision to step down from the helm of the National Constitution Center creates a huge void. It's not an overstatement to say the center owes its existence to Torsella's efforts.

The federal law creating the museum passed in 1988, but little was done until 1996, when then-Mayor Ed Rendell had Torsella, his deputy mayor, appointed president and CEO. Torsella convened a team of scholarly advisers that included Supreme Court Justices Sandra Day O'Connor, Stephen Breyer and Antonin Scalia. He worked tirelessly to raise money to build the facility. Finally, it opened on July 4, 2003.

Torsella then left the center to pursue other dreams, including an unsuccessful run for Congress, but he returned in 2006. He enlisted former President George H.W. Bush to be the center's chairman; former President Bill Clinton will follow Bush. The ex-presidents were 2006 corecipients of the Liberty Medal. In 2007, U2 lead singer and humanitarian Bono received that award, and this year it was given to former Soviet leader Mikhail Gorbachev.

Thousands have visited the center to interact with its exhibits and hear such distinguished speakers as Ruth Bader Ginsburg, Tom Brokaw, Ken Burns, Tom DeLay, Cornel West, Doris Kearns Goodwin, Chris Matthews and Newt Gingrich. Meanwhile, educational programs under the auspices of the Annenberg Foundation have flourished.

Continuing all that good work will be the responsibility of the person chosen to take over after Torsella. He deserves the nation's thanks for the hard work he put into making the National Constitution Center a resounding success.