WASHINGTON - A majority of Americans believe that the harsh interrogation techniques used on terrorism suspects after the 9/11 attacks were justified, even as about half the public says the treatment amounted to torture, according to a new Washington Post-ABC News poll.

By an almost 2-1 ratio, or 59-to-31 percent, those interviewed support the CIA's brutal methods, with the vast majority of supporters saying they produced valuable intelligence.

In general, 58 percent say the torture of suspected terrorists can be justified "often" or "sometimes."

The new poll comes on the heels of a scathing Senate Intelligence Committee investigation into the CIA's detention and interrogation program, which President Obama ended in 2009. The report concluded that controversial interrogation techniques - including waterboarding detainees, placing them in stress positions, and keeping them inside confinement boxes - were not an effective means of acquiring intelligence.

The report also found that more than two dozen detainees were wrongly held, that the program was poorly managed, and that the CIA misled top U.S. officials about the effectiveness of the program.

Fifty-four percent of the public agrees with this sentiment, saying the CIA intentionally misled the White House, Congress and the American people about its activities.

The CIA and former intelligence officials have strongly disputed that assertion. Director John Brennan, while acknowledging the spy agency made mistakes, also disputed the Senate's finding that detainees subjected to enhanced interrogation techniques didn't provide useful intelligence information.

"For someone to say that there was no intelligence of value, of use, that came from those detainees once they were subjected to EITs, I think that is - lacks any foundation at all," Brennan said last week during a rare news conference at the CIA.

He added, however, that "the cause-and-effect relationship" between the use of harsh techniques and useful information subsequently provided by detainees was "unknowable."

Fifty-three percent of Americans say the CIA's harsh interrogation of suspected terrorists produced important information that could not have been obtained any other way, while 31 percent say it did not.

The Post-ABC poll was conducted by telephone Dec. 11 to Dec. 14, among a random national sample of 1,000 adults. The poll had a margin of error of plus or minus 3.5 percentage points.