came to support after opposing the bill for much of the year partly on the ground that it could divert attention from the war on terrorism.

Democratic leaders in Congress, who will appoint half of the 10 members of the commission, immediately named George J. Mitchell, the former Senate majority leader and peace envoy to Northern Ireland and the Middle East, as vice chairman.

The commission's mandate is to conduct a wide-ranging inquiry into the causes of the attacks, whether they could have been averted and what changes are needed to prevent a similar occurrence.

The commission is required to complete its work within 18 months -- a timetable that would have it issue its final report in the middle of a presidential election year -- though Mr. Bush said hehoped it would finish sooner. The leaders of the two parties in Congress must appoint the rest of the members by Dec. 15.

The commission will have the power to issue subpoenas by majority vote, and lawmakers have urged that it cast its net widely and interview current and former government officials, including Mr. Bush and his predecessor, Bill Clinton.

The president cited Mr. Kissinger's long experience in and out of government, including his service as secretary of state in the Nixon and Ford administrations, in putting him in charge of an inquiry intended to explore how failures in intelligence, immigration controls, law enforcement and foreign policy in the Bush and Clinton administrations might have contributed to the deaths of more than 3,000 people in the attacks.

''His investigation should carefully