By David Bauder, Television Writer

NEW YORK (AP) --

After making a documentary about presidential chiefs of staff two years ago, filmmaker Jules Naudet joked about focusing on another important government job where it would seem next to impossible to get interview subjects to speak candidly, if at all.

His new subject? Former directors of the Central Intelligence Agency.

Much to the surprise of Naudet and fellow producers, former CIA chiefs and other key officials agreed to participate. At a time the agency's work seems more important than ever, they talk bluntly about terror threats, drone strikes, secret interrogation sites and torture for a documentary that premieres on Showtime on Saturday at 9 p.m. ET.

The opening of "The Spymasters: CIA in the Crosshairs" illustrates the stakes involved. Former Obama administration director Leon Panetta describes wrestling with decision to order a drone strike on a man suspected of planning the deaths of two CIA agents in an attack dramatized in the movie "Zero Dark Thirty." He knew that women and children would also die if the drone hit its mark. The segment humanizes the job from the start.

"People don't appreciate the responsibilities that the CIA directors have had, especially now," said Susan Zirinsky, CBS News veteran and executive producer. "These are life and death decisions that they have on their hands. I think that gets lost in what people think the CIA is."

Panetta freely acknowledges a drone program that the CIA doesn't officially talk about. During the film, some former CIA officials debate the morality and effectiveness of drone killings, while others won't touch the subject. Former acting director Michael Morell, now a CBS analyst, expresses surprise on camera to learn that others discussed signature strikes.

"These are grown-ups," said Chris Whipple, who interviews each of the directors on camera. "No one tells Bob Gates and Leon Panetta what they can say, which is not to say that they are going to be cavalier."

Former President George H.W. Bush, a CIA director in the Ford administration, was the first interview, and his participation seemed to encourage others.

George Tenet was the last to agree. He's arguably the most important, since his tenure (1997-2004) encompassed the Sept. 11, 2001 terrorist strikes, claims that Saddam Hussein had weapons of mass destruction and opening of secret sites to interrogate suspected terrorists.

"I think he came for history," Whipple said.

Tenet tells of being so alarmed about intelligence indicating an imminent al-Qaida attack that he called the White House on July 10, 2001, and insisted upon coming over immediately for a meeting. "Viewers can judge whether the White House ignored those warnings or not," Whipple said.

Former agency official Cofer Black said in the film that he gets angry when people describe those attacks as an intelligence failure. "We knew this was coming," he said.

Interrogation techniques that some judged as torture — the subject of a scathing Senate Intelligence Committee report a year ago — was a debate topic within the CIA, too. Current director John Brennan expresses regret over not being more vocal about his objections and said he would refuse to waterboard a detainee even if ordered by the president.

Tenet, for his part, said, "we didn't have time to become their best friends."

"I still look at the ceiling at night about a lot of things," Tenet says in the documentary, "and I'll keep them to myself forever."

Each of the directors is at the center of the constant tension between protecting the nation's liberties and ideals while also trying to protect the nation from harm.

To a person, all the wives of the former directors say they could see the toll that the job took on their husbands, who every day learn about horrible things that people want to do to the country. Senior counterterrorism official Gina Bennett talks about how the work negatively affected her home life.

"They feel that they are the soldiers on the front lines and everyone in the country hates them or mistrusts them or thinks that they are out to do the most horrible things," said Gedeon Naudet, Jules' brother and filmmaker partner. "It is extremely dangerous to their psyches, to a point where they even believe that what they say won't matter."

Don't dismiss ego as a motivation for participating in the film, either. Folks like Black and former counterterrorism expert Jose Rodriguez are colorful officials who don't shrink from debating any of the issues involved.

"This was a cast of characters that Aaron Sorkin would not have come up with," Whipple said.

Producers will also make a version of the documentary to air on CBS next year, perhaps updated with current events: last-minutes changes were made for Showtime to incorporate the Paris attacks. There are also discussions about other uses for material collected in the interviews that did not make it into "Spymasters."

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