Attorney General-nominee Eric Holder faced often aggressive grilling from members of the Senate Judiciary Committee Thursday. But one of the first statements made by President-elect Barack Obama's designee to head the Department of Justice during the confirmation hearing was perhaps the most important.

Under oath, with not just senators but the world watching, Holder declared that "waterboarding is torture."

Judiciary Committee chair Patrick Leahy, D-Vermont, referred to waterboarding -- which is broadly recognized as torture but which President Bush, Vice President Cheney and their legal aides defended, at times obliquely, at times overtly -- in his opening round of questions for Holder.

The former Deputy Attorney General responded: "I agree with you Mr. Chairman, waterboarding is torture."

Holder went on to say that "the president does not have the power" to authorize torture.

That statement came during a hearing that saw Holder adopt a humble stance, admitting past mistakes--particularly with regard to his counseling former President Bill Clinton regarding the controversial pardon of fugitive Marc Rich. "I don't mean to minimize what I did by calling it a mistake," the nominee said, under appropriately tough questioning from Pennsylvania Senator Arlen Specter, R-Pennsylvania. "I take what I did seriously and have expressed regret for what I did consistently."

Holder also expressed a regard for the Constitution that was rarely in evidence during the Bush-Cheney years.

Conscious of criticism he has taken for being too deferent to the presidents he has served in the past, Holder placed special emphasis on his understanding of his responsibility to serve not just the man who is appointing him but the Constitution.

Holder promised to be a "guardian of the document" and recognized that "congressional review and judicial oversight are necessary."

Holder is not a perfect nominee. He will not be a perfect Attorney General. But his declaration to the committee that the Department of Justice must serve not a president or a party but the Constitution and the American people was a refreshing indication that Holder "gets it" in ways that Alberto Gonzales and Michael Mukasey never did.

That said, while Holder's statements were important, he should also have been listening to the committee charged with providing not just consent but advice to the new administration and its Attorney General.

"We need an Attorney General, as Robert H. Jackson said 68 years ago, 'who serves the law and not factional purposes, and who approaches his task with humility,'" said Leahy in his opening statement. "The next Attorney General will understand our moral and legal obligation to protect the fundamental rights of all Americans and to respect the human rights of all people."

Leahy says he believes Holder will be that sort of Attorney General.

And Holder provided some evidence on Thursday that he would meet the standard. In so doing, he did his nomination prospects good service -- all but assuring that the man many see as the president-elect's most vulnerable nominee will be approved by the committee and confirmed by the full Senate.

Once that happens, Holder's first task should be to reward this confidence by using his powerful position to give meaning to his testimony of Thursday by assuring that no one detained by the United States will ever again be subjected to the torture that is waterboarding.