It was the 10-member group created by a congressional act signed by the president on November 27, 2002. The bipartisan commission, consisting of five Republicans and five Democrats, was chosen by Congress to look into how the attacks of September 11, 2001, could have happened and how such a tragedy could be avoided in the future. During its investigation, the commissioners and their staff reviewed more than 2.5 million pages of documents, interviewed more than 1,200 people in 10 countries, held 19 days of hearings, and took public testimony from 160 witnesses. The commission wrapped up its work in all due speed, publishing a full report less than two years after it received its mandate. The 567-page report chronicles the events of 9/11, looks at the roots and growth of the “new terrorism,” reviews the U.S. response to the attacks and to previous assaults (including the August 1998 U.S. embassy bombings in Kenya and Tanzania), and recommends changes to prevent further terrorist strikes. The report was made available as a book and an online document, presented “to the American people for their consideration.”

Among the key disclosures in the report were that the commission found “no credible evidence that Iraq and al Qaeda cooperated on the attacks against the United States.” That finding was immediately dismissed by the White House in June 2004. The commission also reported that the original plan for the al Qaeda attacks on the U.S. homeland included a total of 10 hijacked airplanes, striking targets on the East and West coasts; the plan was dismissed by al Qaeda leader Osama bin Laden as too complex. In the aftermath of the 9/11 attacks and the U.S.-led retaliatory strikes on Afghanistan, the commission believed that al Qaeda had become more decentralized, with cell leaders assuming greater authority for decision-making.