When the Justice Department publicly declared torture “abhorrent” in a legal opinion in December 2004, the Bush administration appeared to have abandoned its assertion of nearly unlimited presidential authority to order brutal interrogations.

But soon after Alberto R. Gonzales’s arrival as attorney general in February 2005, the Justice Department issued another opinion, this one in secret. It was a very different document, according to officials briefed on it, an expansive endorsement of the harshest interrogation techniques ever used by the Central Intelligence Agency.

The new opinion, the officials said, for the first time provided explicit authorization to barrage terror suspects with a combination of painful physical and psychological tactics, including head-slapping, simulated drowning and frigid temperatures.

Mr. Gonzales approved the legal memorandum on “combined effects” over the objections of James B. Comey, the deputy attorney general, who was leaving his job after bruising clashes with the White House. Disagreeing with what he viewed as the opinion’s overreaching legal reasoning, Mr. Comey told colleagues at the department that they would all be “ashamed” when the world eventually learned of it.

Later that year, as Congress moved toward outlawing “cruel, inhuman and degrading” treatment, the Justice Department issued another secret opinion, one most lawmakers did not know existed, current and former officials said. The Justice Department document declared that none of the C.I.A. interrogation methods violated that standard.

The classified opinions, never previously disclosed, are a hidden legacy of President Bush’s second term and Mr. Gonzales’s tenure at the Justice Department, where he moved quickly to align it with the White House after a 2004 rebellion by staff lawyers that had thrown policies on surveillance and detention into turmoil.

Congress and the Supreme Court have intervened repeatedly in the last two years to impose limits on interrogations, and the administration has responded as a policy matter by dropping the most extreme techniques. But the 2005 Justice Department opinions remain in effect, and their legal conclusions have been confirmed by several more recent memorandums, officials said. They show how the White House has succeeded in preserving the broadest possible legal latitude for harsh tactics.

“It takes far more than a sharp legal mind to say ‘no’ when it matters most,” he said. “It takes moral character. It takes an understanding that in the long run, intelligence under law is the only sustainable intelligence in this country.”

Senator Barack Obama (D-IL) signed the American Freedom Pledge yesterday, expressing his commitment to protecting and defending the Constitution. With Senator Obama's pledge, all of the Democratic presidential candidates except Senator Hillary Clinton (D-NY) have now either signed the pledge or have provided the American Freedom Campaign Action Fund with a detailed statement addressing the issues described in the American Freedom Campaign Agenda. (The full agenda is included at the bottom of this release.)

The American Freedom Campaign (AFC) Action Fund is encouraging all candidates to sign this pledge, the text of which is as follows:

"We are Americans, and in our America we do not torture, we do not imprison people without charge or legal remedy, we do not tap people's phones and emails without a court order, and above all we do not give any President unchecked power.

"I pledge to fight to protect and defend the Constitution from attack by any President."

The Campaign also sent letters in August to the announced Republican presidential candidates. None of the Republican candidates have provided AFC with a response. Earlier this year, however, Representative Ron Paul (R-TX) signed a similar pledge circulated by the American Freedom Agenda, an organization formed by conservative leaders, including former Reagan official Bruce Fein and former congressman Bob Barr.

For more details about the American Freedom Campaign Action Fund's presidential pledge campaign, including the written responses from two of the candidates, please visit this page.

The mission of the American Freedom Campaign is to preserve the vision of the nation's Founders -- that no President shall be above the law. As part of this mission, it seeks to make the issue of defending the Constitution a prominent part of the 2008 presidential campaign. Later this fall, with a grassroots army to call on, the Campaign intends to turn up the heat on candidates who have not made their commitment to defending the Constitution clear.