SEATTLE — The two psychologists who helped design the CIA’s harsh interrogation methods used in the war on terror are battling with a civil liberties group over their responsibility for detainees being subjected to waterboarding and beatings following the Sept. 11 attacks.

Lawyers for the psychologists say they should be as free from liability as a worker for a company that supplied the Nazis with poison gas used in concentration camps.

The American Civil Liberties Union is challenging that claim, saying psychologists James Mitchell and Bruce Jessen should be held accountable for the methods they crafted. The group has sued the pair on behalf of three former detainees, including one who died in custody.

Both sides will appear today before a U.S. judge in Spokane, Wash. The outcome of the arguments in U.S. District Court will determine whether the lawsuit goes to trial, set for Sept. 5.

The judge could decide the psychologists are guilty of aiding and abetting torture and no trial is needed. He also could dismiss the suit or limit what claims can be pursued.

Like the gassing technician who was acquitted on charges of helping the Nazis, the Spokane psychologists were independent contractors who lacked authority to “control, prevent or modify” the CIA’s use of enhanced interrogation techniques, their lawyers said.

The ACLU is challenging that argument on behalf of Suleiman Abdullah Salim, Mohamed Ahmed Ben Soud and a representative of Gul Rahman, who were subjected to physical assaults and sleep deprivation, forced to stand for days in diapers with their arms chained overhead, doused with icy water and stuffed into boxes.

“In fact, the Nuremberg tribunals that judged the Nazis and their enablers after World War II established the opposite rule: Private contractors are accountable when they choose to provide unlawful means and profit from war crimes,” said Dror Ladin, an American Civil Liberties Union lawyer.

Mitchell and Jessen came up with the “torture methods,” personally tested them on the CIA’s first prisoner and formed a company that earned $81 million to run the program, Ladin said.

“Making money by choosing to supply the tools for torture isn’t ‘simply doing business,’” Ladin said. “It’s illegal.”

The psychologists’ lawyers say they hoped to “prevent another catastrophic attack on the United States.”

When the CIA asked for help interrogating Abu Zubaydah, a “high value” detainee, Mitchell suggested methods used for decades at an Air Force school, his lawyers said. When the CIA asked for more details, Mitchell provided them and brought in Jessen.

The techniques were designed to motivate a person to provide information, “while avoiding permanent physical harm or profound and pervasive personality change,” defense lawyers said. Mitchell and Jessen “never acted beyond the scope of their CIA contracts,” the attorneys said.

They noted the lawsuit over the 2010 Gulf of Mexico oil spill, in which federal contractors received immunity from clean water laws for any damage resulting from their actions as long as they acted within the government’s directives.

In this case, the White House ordered the capture and interrogation of al-Qaida operatives and the CIA hired the psychologists. Therefore, the government’s immunity extends to Mitchell and Jessen and the lawsuit should be thrown out, their lawyers said.

The ACLU said there’s a legal and moral imperative to hold the men accountable.

Mitchell helped implement interrogation techniques used on Zubaydah that began with extreme sensory deprivation, shifted to coercive methods to instill fear and despair, then moved to assaults, waterboarding and stuffing him into coffinlike boxes, the ACLU said.

Zubaydah “cried, begged, pleaded, vomited, trembled, shook and became so hysterical he could not communicate,” the group’s lawyers said.

By 2003, the methods were formalized in instructions sent to a secret CIA prison where the plaintiffs in the lawsuit were tortured, the ACLU said. Mitchell and Jessen participated in some interrogations, the lawyers said.

When Jessen observed prolonged physical assaults on Rahman, his reaction “was to opine that it was worth trying” and suggested alterations, the ACLU said.

After those methods were added, Rahman, “starved, sleepless and freezing,” died of hypothermia.