WASHINGTON - Barack Obama's choice to run the US Justice Department, Eric Holder, drew a line under Bush administration anti-terror policy, calling waterboarding torture.
Attorney general designate Holder also said at his Senate confirmation hearing that the Obama team, which takes office Tuesday, was already taking steps to prepare the closure of the Guantanamo Bay "war on terror" prison.
Holder, who would be the first African-American in the job, also had to play some defense, as Republicans grilled him over his role in the pardon of fugitive financier Marc Rich in the Clinton administration.
He told the Senate Judiciary committee that Obama's administration would ensure US anti-terrorism policies were faithful to fundamental American values and the "letter and spirit of the Constitution."
"Waterboarding is torture," Holder said, in the dramatic opening salvos of the hearing before the Senate Judiciary Committee.
Waterboarding, or simulated drowning, was used in the Spanish Inquisition and by Cambodia's Khmer Rouge, and the CIA has admitted it used the technique on several of the top Al-Qaeda plotters of the September 11 attacks in 2001.
The practice has been fiercely condemned by human rights groups, which also have concerns about other "enhanced interrogation techniques."
The two most recent attorney generals under President George W. Bush had declined to go as far as Holder on waterboarding, and Vice President Dick Cheney has defended the practice, saying it yielded vital intelligence.
Holder was also asked whether he believed that the US president had the constitutional power to declare an act of torture within the law.
"No one is above the law, the president has a constitutional obligation to faithfully execute the law of the United States," said Holder.
Holder, a career lawyer and former justice department official, reiterated Obama's pledge on Guantanamo Bay, which has tarnished the US image abroad.
"Guantanamo will be closed," Holder said. He declined to give a date for the closure, but said that "steps are being taken as we speak."
Obama has said that closing the camp will take longer than many of his supporters had hoped.
On Monday, President George W. Bush said he hoped his Obama would carefully weigh keeping controversial interrogation tactics and other aspects of his "war on terror" policies.
Holder admitted the Bush administration had faced difficult decisions on how to deal with terror captives following the September 11 attacks in 2001.
"Having said that, the president-elect and I are worried, disturbed by what we have seen and heard.
"I will use every available tactic to defeat our adversaries and I will do so within the letter and spirit of the constitution," Holder told the committee.
President-elect Obama has vowed that the United States will not use torture under his watch, following claims the Bush administration subverted the limits of its constitutional powers and the Geneva Conventions with its treatment of "war on terror" detainees.
Holder's appearance had a certain historical poignancy, as it took place in an ornate Senate hearing room on the day civil rights icon Martin Luther King would have turned 80 years old.
He also faced intense questioning over former president Bill Clinton's decision to pardon fugitive financier Marc Rich during the waning hours of his administration in 2001.
Holder was a deputy attorney general at the time and said he regretted his role in vetting the pardon, which was vigorously criticized after Clinton left office.
"I've accepted the responsibility of making those mistakes, I've never tried to hide, I've never tried to blame anybody else."
The senior Republican on the committee Senator Arlen Specter complained there had been insufficient time to vet Holder, saying he had been unable to obtain records from the Clinton presidential library.
But Leahy warned Holder's nomination was for a vital post and his confirmation should not be held up over "partisan bickering."
Holder also vowed to restore the morale of the Justice Department, which was rocked by allegations in the Bush administration that plum government jobs were handed out only to conservatives or supporters of the White House.