President Bush yesterday appointed former New Jersey governor Thomas H. Kean to lead the prominent new commission that will investigate the Sept. 11, 2001, terrorist attacks, three days after the abrupt resignation of former secretary of state Henry A. Kissinger, the administration's first choice.

Bush announced the selection of Kean, a moderate Republican and a university president for the past dozen years, to replace Kissinger, who surprised the White House by withdrawing before the commission began its work, Kissinger cited widespread concern over potential conflicts of interest involving his business interests.

Kean, a popular governor from 1982 to 1990, is widely perceived as independent-minded and skillful at management. But skeptics said he lacks expertise in immigration, intelligence, security and other realms the commission will explore as it tries to ferret out the governmental lapses that allowed the terrorist hijackings to succeed.

According to administration officials, lawmakers and advocates who lobbied for creation of the National Commission on Terrorist Attacks, Kean will bring very different characteristics to the panel.

"While he doesn't have Henry Kissinger's depth in international affairs, he has a proven track record of bringing people together and finding unity," one administration official said.

The White House portrayed Kean as close to families who lost relatives in the attacks. Kean said yesterday that the main reason the administration had mentioned in offering him the position Sunday night was his roots in the part of the country that had suffered the greatest losses.

Bush announced his selection on the same day that Senate Republican leader Trent Lott (Miss.) named a former Navy secretary, John Lehman, as the 10th -- and final -- member of the commission. In choosing Lehman, Lott spurned former senator Warren B. Rudman (R-N.H.), the choice of two Republican senators who have been intimately involved with the commission's creation.

Rudman, who helped lead a separate inquiry that exposed the nation's vulnerability to terrorism, was promoted for the new panel by victims' families and had been backedby Sens. John McCain (Ariz.) and Richard C. Shelby (Ala.).

The appointments of Kean and Lehman complete the membership of an inquiry panel whose necessity, purpose and participants have been disputed for months. Like Kissinger, former Senate majority leader George J. Mitchell (D-Maine), the Democrats' initial choice for vice chairman, quit the panel even before it began its 18-month investigation. Mitchell also said he was deterred by the possibility that he would have to forsake some private sector work to make the commission truly neutral.

By yesterday, the panel's most ardent champions suggested that the commission probably had attained neutrality, but might lack aggressiveness or expertise as a result.

Kean, in particular, "doesn't have the background in any of the areas that the commission will be [probing] -- diplomacy, aviation security, immigration policy, intelligence," said Stephen Push, a spokesman for Families of September 11, one of the family groups that welded their grief into a lobbying force for the commission.

Outgoing Rep. Timothy J. Roemer (D-Ind.), who helped write the legislation creating the commission and is one of its members, said the panel "is off to a bit of a bumpy start" but predicted, "we will be in very good shape," as long as it "doesn't get into a partisan wrangling game."

Roemer said that, while he believes Rudman would have brought "fierce independence" to the group's work, Kean has a background of "moderation and working across the aisle."

The commission will be the second to examine government failures that allowed the attacks. An investigation by the House and Senate intelligence committees turned up numerous lapses by the FBI, CIA and other agencies.

The commission is equally divided between GOP and Democratic appointees. Advocates are wary that the panel, which will require six votes to issue a subpoena, may prove reticent to embarrass the administration by probing deeply into executive branch agencies that did not detect or thwart the terror plot.

White House press secretary Ari Fleischer said the possibility of Kean as chairman was first broached to Bush in late October by the president's chief of staff, Andrew H. Card Jr. "Andy started bouncing several names off the president," Fleischer said, adding that Kissinger was discussed at the same time.

At a news conference at Drew University in Madison, N.J., where he is president, Kean said he spoke to the White House Saturday, the day after Kissinger stepped down. Several conversations later, Kean said, Card telephoned him Sunday night to ask: "Do you want to do it?"

Kean said his relationship with Bush is "cordial" and that they had met "a couple of times." In the past, Kean has publicly distanced himself from elements of his own party, saying in 1995 that he was disturbed by the growing influence of "right-wing radicals" in the GOP.

Yesterday, Kean sought to put to rest the matter of conflicts of interest, saying, "I have no clients except the university." He said that he would remain the school's president, devoting one day a week to the commission's work.

In a statement, Bush called Kean "a leader respected for his integrity, fairness and good judgment," and said he expected that he would assure that the commission's work is "thorough."

Fleischer said Kean has a "very close relationship with the 9/11 families," noting that he is a board member of a company that lost 80 employees in the attack on New York's World Trade Center.

Kean identified the firm as Fiduciary Trust International and said he had spoken at a memorial service for its employees after the attacks.

Correspondent Robert Strauss contributed to this report.

Thomas H. Kean now leads a N.J. university.Former New Jersey governor Thomas H. Kean, speaking at a news conference at Drew University in Madison, N.J., where he is president, said he would devote one day a week to the panel.