Following the revelation that President George W. Bush not only approved of but emphatically supported his administration's torture program, a growing chorus of lawmakers and human rights groups has expressed outrage at the lack of investigations and prosecutions.

Torture is illegal under US and international law, including the UN Convention Against Torture and the Geneva Convention relative to the Treatment of Prisoners of War, which claims the US as a signatory.

Though interrogators employed a variety of torture techniques, the use of waterboarding has attracted the most coverage by US media. Waterboarding, or simulated drowning, was carried out against American soldiers by the Japanese during World War II, and later prosecuted as a war crime.

The same cannot be said for the Bush administration.

"It is absolutely vital that a thorough review of President Bush’s now admitted ordering of waterboarding take place," Rep. John Conyers (D-MI) said in a Friday media advisory. "We are a nation of laws, not men, and the domestic and international laws – including the Convention Against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment – governing the use of torture are clear in their scope and application. There is no exception for the President or any other official and no lawyer’s opinion can provide immunity from these laws."

Conyers, a longtime proponent of investigating the prior administration's extralegal activities, is just the latest in a new tide of calls for justice. While the issue has been dormant in the US media for months as the midterm election campaigns dominated headlines, now that the outlay of Congress has been decided lawmakers are pressing the issue anew.

And it was Bush himself who punted the issue back into the national discussion. In his book Decision Points, the former president asserts that he was asked by the Central Intelligence Agency whether he would support the agency's waterboarding of Khalid Sheik Mohammed, the alleged 9/11 mastermind.

"Damn right," Bush admits he told the CIA.

And it was all legal "because the lawyer said it was," Bush told NBC's Matt Lauer during a recent interview.

"He said it did not fall within the anti-torture act," he said. "I'm not a lawyer, but you gotta trust the judgment of people around you and I do."

It was an obvious reference to the infamous "torture memos" penned by the Justice Department's Office of Legal Council (OLC). Those memos were made public in 2009, in response to an American Civil Liberties Union (ACLU) Freedom of Information Act request.

Though the current administration expressly forbids the use of torture, attorneys with Obama's Justice Department have staunchly defended lawyers who advocated torture, saying they must be immune to prosecution because they were giving legal advice to the president during wartime.

John Yoo, while at the Office of Legal Council in 2002, authored a majority of the department’s opinions on torture along with Jay Bybee, who now serves as a judge on the U.S. 9th Circuit Court of Appeals, and Steven Bradbury, the former OLC chief who now practices law in Washington, D.C.

Bush's book isn't the first time he admitted supporting the use of torture: in June he told a crowd in Grand Rapids, Michigan that if it were up to him he'd approve it again. Former Vice President Dick Cheney has also admitted his express support for waterboarding, even calling it "well done".

In a letter to Attorney General Eric Holder (.pdf) Wednesday, the ACLU noted, "The Department of Justice has made clear that waterboarding is torture and, as such, a crime under the federal anti-torture statute."

Holder has tapped Assistant US Attorney John Durham to look into whether the CIA or contractors went beyond legal interrogation methods. That investigation is ongoing, according to NPR. But the scope of Durham's investigation does not include White House officials.

"In light of the admission by the former President, and the legally correct determination by the Department of Justice that waterboarding is a crime, you should ensure that Mr. Durham's current investigation into detainee interrogations encompasses the conduct and decisions of former President Bush," wrote ACLU Executive Director Anthony Romero.

"I have also urged the Department to reconsider the recent decision not to pursue justice against those responsible for destroying videotape evidence involving water boarding by the CIA," Conyers concluded. "The Justice Department should do its duty here and uphold the law in both of these matters, and if not, Congress needs to act."

Amnesty International Senior Director Claudio Cordone said in a statement that the Obama administration must prosecute the former president.

"If his admission is substantiated, the USA has the obligation to prosecute him," he said. "In the absence of a US investigation, other states must step in and carry out such an investigation themselves."

It is highly unlikely that Republicans, who will control the US House of Representatives when the next Congress begins work in 2011, will have much appetite to investigate the prior administration. Even so, one newly elected Republican member, Rep. Jason Chaffetz (R-UT), said recently that he would have "no hesitation" in joining an effort to investigate the Bush administration's torture program.