The speaker had hardly finished his first sentence when about 25 Yale Law School students in the audience stood up and sheathed their heads in black trash bags, in imitation of hooded military prisoners at the Abu Ghraib prison in Iraq.

The students were protesting an appearance at the Law School on Thursday evening by Jay Bybee, a judge on the U.S. Court of Appeals for the Ninth Circuit who, when he was head of the Bush administration’s Office of Legal Counsel, signed off on a controversial policy for interrogation and detention of “military combatants” — what critics have labeled the “torture memo.”

Bybee’s speech was billed as a debate with Yale Law professor Steven Duke about federalism and criminal law, but for at least two dozen audience members, the address was primarily an opportunity to confront Bybee. The event — hosted by the Yale chapter of the Federalist Society, an organization of conservative and libertarian law students — was reserved exclusively for law students and closed to the press, but the proceedings were visible from the hallway.

“Jay Bybee helped formulate policies that violated hundreds of people’s human rights,” protest organizer Darryl Li LAW ’09 said in an interview after the demonstration. “He was never held accountable for what he did but rather was promoted to a very powerful position in the federal judiciary.”

Christopher Angevine LAW ’08, president of the Federalist Society, declined to comment on the event Thursday night.

Several members of the Law School faculty have been vocal opponents of Bush administration policies on the war on terror. Dean Harold Hongju Koh testified before Congress in 2006 against the warrantless domestic wiretapping program. And last month, Law School visiting lecturer Jonathan Freiman LAW ’98 and Yale’s Lowenstein International Human Rights Clinic filed suit against John Yoo LAW ’92 on behalf of Jose Padilla — who was convicted of conspiracy to murder and kidnap people overseas — for Yoo’s role in drafting Bybee’s memo.

Before the event, the protestors convened in the Law School auditorium, where Li distributed trash bags and briefed them on the plan. The participants were an informal group of students, Li said.

“This is an issue that’s important to the world and to the nation, but especially to us as law students, because Bybee is a shameful example of how placing power above principle violates the rule of law and dishonors the legal profession,” Li said.

At the door of the lecture hall, which was guarded by a police officer, two students handed out fliers titled “STAND UP TO TORTURE.” One of them said she offered a flier to Bybee when he entered, but he turned it down.

The program began at 6:10 p.m. with an introduction by the Federalist Society’s vice president for events, Adam Gustafson LAW ’09. Those in the half-full lecture hall applauded as Bybee ascended to the lectern.

But as he began to speak, the protesters, clustered in the center seats, stood and pulled the bags over their heads. A few other audience members clapped, several of the protesters said afterward. Bybee, visibly annoyed, stopped speaking.

“If you’re blocking other people from seeing, you have to leave,” Li said Gustafson told the protesters. Gustafson paused, then said, “You are blocking people. You have to leave.”

The protestors removed the bags and laid them at the foot of the lectern as they walked out. Bybee then went on the speak for about 30 minutes.

Li said he was involved in a similar protest when Bybee spoke at Harvard Law School in 2006.