(CBS) President Bush on Monday named former New Jersey Gov. Thomas Kean to replace Henry Kissinger as chairman of the panel investigating the Sept. 11, 2001 terrorist attacks.

"Tom Kean is a leader respected for integrity, fairness and good judgment," the president said in a prepared statement. "I am confident he will work to make the commission's investigation thorough. It is important that we uncover every detail and learn every lesson of Sept. 11."

Kean, currently president of Drew University in Madison, N.J., was New Jersey governor from 1982 to 1990.

Kissinger, the former secretary of state, stepped down Friday as chairman of the panel, citing controversy over potential conflicts of interest with his private-sector clients.

Some Democratic lawmakers had demanded that Kissinger make public the names of all of the clients of his consulting firm. The White House argued that he didn't have to do that, but Kissinger resigned anyway.

Two days before Kissinger's abrupt withdrawal, former Sen. George Mitchell, D-Maine, stepped down as vice chairman. Democrats replaced Mitchell with former Rep. Lee Hamilton, D-Ind.

The twin resignations came as the commission hoped to get to work next month after resolving disputes about its organization and its authority to issue subpoenas.

House Speaker Dennis Hastert on Sunday named a former Illinois governor and a former White House counsel to serve on the panel.

Hastert, R-Ill., appointed former Gov. Jim Thompson and attorney Fred Fielding to the 10-member panel. Republicans and Democrats each get to appoint five committee members.

Thompson was Illinois' longest-serving governor, holding four terms from 1977 to 1991. He is now chairman of the Chicago-based law firm of Winston & Strawn.

Senate Republican leader Trent Lott of Mississippi already has named former Sen. Slade Gorton, R-Wash., but has not announced his second choice. Lott has promised to consult with Sen. John McCain, R-Ariz., a close ally of the Sept. 11 families, in choosing his second appointee.

The families and McCain have been pushing for former Sen. Warren Rudman, R-N.H., who led an advisory group that warned of U.S. vulnerability to terrorist attacks before Sept. 11.

Democrats have named five members, including Hamilton. The others are: outgoing Sen. Max Cleland, D-Ga.; outgoing Rep. Timothy Roemer, D-Ind.; attorney Richard Ben-Veniste and Jamie Gorelick, a deputy attorney general under President Clinton.

The commission, formally known as the National Commission on Terrorist Attacks, will investigate events leading up to the attacks, including aviation security, immigration and U.S. diplomacy. It is to build on the work of a recently completed congressional inquiry into intelligence failures.

Kean, 67, served two terms as governor before leaving office in 1990. Many state and national Republican leaders, including President Bush, had urged Kean to challenge Democrat Robert Torricelli for Senate last year, but he declined. Instead, he served as chairman of Republican Doug Forrester's unsuccessful Senate campaign.