Former FBI agent Ali Soufan in Alex Gibney's HBO documentary 'The Forever Prisoner.'
CNN  — 

If a goal of the Sept. 11 terrorists was to undermine American values, “The Forever Prisoner” makes the case on that score, at least, the bad guys won. Focusing on the treatment of Abu Zubaydah, a former associate of Osama bin Laden held in detention since 2002, director Alex Gibney’s HBO documentary argues the US response marked “our retreat from the ideals we claim to be fighting for.”

Gibney (who again narrates the film) manages to interview several key players in the counter-terrorism fight, meticulously documenting the extent to which the government compromised established guardrails in the name of safety and security.

Lawrence Wilkerson, Colin Powell’s former chief of staff, says the stunning nature of the Sept. 11 attacks “made us stupid.” The prevailing belief, the film notes, was that all bets were off in dealing with the perpetrators, who by virtue of their actions “had opted out of the human race.”

Gibney contends the terrorists had thus effectively provoked the US government “to abandon the principles of democracy that we claim to live by.” The nature of how those principles were bent fell directly on Zubaydah, the first detainee subjected to what were bureaucratically known as Enhanced Interrogation Techniques.

Although former FBI agent Ali Soufan indicates that more conventional interrogation methods began to bear fruit in breaking down Zubaydah’s resistance, the program forged ahead with more brutal methods. (Gibney sued the CIA to un-redact portions of Soufan’s book “The Black Banners: How Torture Derailed the War on Terror after 9/11,” which he had previously been unable to publicly discuss.)

“Forever Prisoners” presents detailed descriptions of waterboarding sessions and includes an interview with CIA contractor James Mitchell regarding such practices. Although some officials have objected to characterization of the policy shift as allowing torture, the documentary illustrates misgivings about it at the time, with Jose Rodriguez, the former director of CIA’s Counterterrorism Center, telling subordinates, “Do not put your legal concerns in writing. Not helpful.”

The damning revelations found in the Senate Intelligence Committee report on the program, also dramatized in the movie “The Report,” highlighted the government’s actions. Two decades later, Zubaydah remains incarcerated at Guantanamo Bay, prompting Gibney – whose recent HBO documentaries include “The Crime of the Century” and “Agents of Chaos” – to ask, “How can we imprison a man, without charge, for the rest of his life?”

In that and other ways, “The Forever Prisoner” asks the right questions regarding not just Zubaydah but the broader prosecution of the war against terrorism. As the film makes clear, it’s the answers that have proven elusive.

“The Forever Prisoner” premieres Dec. 6 at 10 p.m. ET on HBO, which, like CNN, is a unit of WarnerMedia.