The report provided previously undisclosed details about the legal and operational schisms that dogged the program in its five years of existence. The 38-page document released Friday was an unclassified version. The bulk of the findings remain classified in separate reports from each of the five inspectors general, who represent the Justice Department, the N.S.A, the C.I.A., the Defense Department and the Office of National Intelligence.

Image John Yoo in 2001 issued an endorsement of warrantless wiretapping from the Justice Departments office of legal counsel. Credit... Susan Walsh/Associated Press

The inquiry included interviews with about 200 government and private-sector personnel, but a number of key players  including David Addington, a top aide to Mr. Cheney; George J. Tenet, the former C.I.A. director; John Ashcroft, the former attorney general; and John Yoo, a Justice Department lawyer who endorsed the wiretapping program  declined to be interviewed.

Congressional Democrats who had been critics of the program said they found the report’s conclusions disturbing.

“While former Bush administration officials continue to argue that their policies made the country safer,” said Senator Ron Wyden, Democrat of Oregon, “I believe this report shows that their obsession with secrecy and their refusal to accept oversight was actually harmful to U.S. national security, not to mention the privacy rights of law-abiding Americans.”

A statement from Dennis Blair, the current director of national intelligence, said he was committed to “seeing that all surveillance activities protect U.S. national security and comply with the laws of the United States.”

Among other findings, the report concluded that Alberto R. Gonzales, as attorney general, provided “confusing, inaccurate” statements about N.S.A. surveillance activities to lawmakers in 2007, but did not “intend to mislead Congress.” Mr. Gonzales had said that a dispute between the White House and Justice Department lawyers in 2004 did not relate to the wiretapping program but rather to “other” intelligence activities.

The report states that at the same time Mr. Bush authorized the warrantless wiretapping operation, he also signed off on other surveillance programs that the government has never publicly acknowledged. While the report does not identify them, current and former officials say that those programs included data mining of e-mail messages of Americans. That was apparently what Mr. Gonzales was referring to in his Congressional testimony.