Also in the fall of 2005, the U.S. Supreme Court heard a case involving the legal rights of detainees held at Guantanamo Bay Naval Base. It decided in June 2006 that al Qaeda prisoners are protected by the Geneva Conventions' prohibitions of torture and cruel treatment.
At the time, the CIA also was worried that its operatives involved in prisoner interrogation might be subject to legal charges involving treatment of detainees. Some agency employees have bought liability insurance as a hedge against that possibility.
The decision to destroy the tapes was made by Jose Rodriguez, then the head of the CIA's clandestine directorate of operations under CIA Director Porter Goss.
Hayden said members of the congressional intelligence committees were made aware in February 2003 both of the tapes and the CIA's ultimate plan to destroy them. That claim was denied by several members of the panels, including Republican Rep. Peter Hoekstra, who at the time was chairman of the House Intelligence Committee.
The Senate Intelligence Committee did not learn of the tapes' destruction until November 2006, and Chairman Jay Rockefeller, who then was the ranking minority member on the committee, said he was not told in 2003 of the plan to destroy them. The House Intelligence Committee learned of the tapes' destruction in March 2007.
Republicans were mostly silent about the CIA disclosure. McCain, a presidential candidate, said while campaigning in New Hampshire Friday that he would not side with the Democrats' calls for an investigation because he believed the CIA's actions were legal.
"That doesn't mean I like it," McCain added.
"Of course I object to it," he said of the tapes being destroyed. "Right now, our intelligence agencies need credibility, and this is not helpful to that."
At least one of the tapes showed the interrogations of Abu Zubaydah, the first high-value detainee taken by the CIA in 2002. Zubaydah, under harsh questioning, told CIA interrogators about Ramzi Binalshibh, the alleged accomplice in the Sept. 11, 2001, terror attacks, Bush said publicly in 2006. The two men's confessions also led to the capture of Khalid Sheikh Mohammed, whom the U.S. government said was the mastermind behind the Sept. 11 attacks.
Hayden told agency employees the interrogations were legal, and said the tapes were not relevant to "any internal, legislative or judicial inquiries."
Lawyers for U.S. detainees believe otherwise.
The Center for Constitutional Rights, which coordinates the work of all attorneys representing U.S. prisoners held at Guantanamo Bay Naval Base, says the CIA may have destroyed crucial evidence a court said it was entitled to in 2004.
The center said Friday it is now "deeply concerned" the CIA may have destroyed evidence relating to Majid Khan, a former CIA detainee now held at Guantanamo.
Amnesty International, another prominent global human rights organization that regularly criticizes the U.S. government's secret detention and interrogation practices, also sharply criticized the tapes destruction.
"It falls into a pattern of measures that have been taken that obstruct accountability for human rights violations," Amnesty spokesman Rob Freer told CBS News reporter Larry Miller.
Revelations about the tapes also may affect current terror trials.
Convicted terror conspirator Jose Padilla's lawyers claimed in a Florida federal court that Abu Zubaydah was tortured into saying Padilla was an al Qaeda associate. The Justice Department dismissed Padilla's allegations as "meritless," saying Padilla's legal team could not prove that Abu Zubaydah had been tortured.
Padilla and his two co-defendants will be sentenced next month. They face life in prison on three terror-related convictions.
Then-U.S. District Judge Mukasey, now attorney general, signed the warrant used by the FBI to arrest Padilla in May 2002. That warrant relied in part on information obtained from Abu Zubaydah, court records show.
In a separate case, attorneys for al Qaeda conspirator Zacarias Moussaoui in 2003 began seeking videotapes of interrogations they believed might help their client. In November 2005 a federal judge ordered the government to disclose whether it had video or audio tapes of specific interrogations. Eleven days later, the government denied it had them.
Gerald Zerkin, one of Moussaoui's lawyers in the penalty phase of his trial, recalled some of the defense efforts to obtain testimony from or video or audio tapes of the interrogations of top al Qaeda detainees. "Obviously the important witnesses included Zubaydah, Binalshibh and KSM (Khalid Sheikh Mohammed). ... Those are the guys at the head of the witness list," Zerkin said. He could not recall specifically which tapes he requested or the phrasing of his discovery requests, which he said were probably still classified.
The tapes also were not provided to the special commission that studied government actions before and after the 2001 attacks. The commission relied heavily on intelligence reports about Abu Zubaydah and Binalshibh's 2002 interrogations. CIA spokesman Mark Mansfield said the agency did not subvert the 9/11 commission's work.
"Because it was thought the commission could ask about tapes at some point," he said, "they were not destroyed while the commission was active."