"We all have our moments," says Yuval Diskin, calm, thoughtful, disturbed. "Maybe you're shaving and you think, 'I make a decision and x number of people are killed.' The power to take lives in an instant, there's something unnatural about it."

The "we" in that compelling statement refers to a very small group of individuals, the men who, like Diskin, have been the heads of Shin Bet, Israel's shadowy, supersecret domestic counterterrorism agency, the men profiled in "The Gatekeepers," an Oscar-nominated documentary potent enough to alter the way you see the world.

"The Gatekeepers" is a coup for Israeli director Dror Moreh, who did what sounds impossible: He persuaded all six living former heads of Shin Bet, the men who ran the agency from 1980 through 2011, to speak publicly for the first time about their work combating violence from both Palestinians and Israelis.

To call the blisteringly candid results eye-opening is not even to scratch the surface.

Riveting from beginning to end, "The Gatekeepers" works in a pair of complementary ways: as a portrait of half a dozen compelling individuals, no two alike, and as a chronological history of the state of Israel from the end of the Six-Day War in 1967 to the present. It's the autobiography of a country, if you will, told by ultimate insiders.

The noteworthy thing about the six is that, though they couldn't be more different -- in fact, they take the occasional sharp jab at each other -- they are alike in a number of intriguing ways.

As befits their occupation, these speakers -- Avraham Shalom, Yaakov Peri, Carmi Gillon, Ami Ayalon, Avi Dichter and Diskin -- are somber, serious and highly intelligent. They're impressive commanders who lack neither the confidence nor the nerve to do whatever the situation demands. Yet these men also demonstrate how soul-destroying it can be for moral individuals and societies to cope with situations that almost mandate behavior that may seem amoral or even immoral. Far from being soulless and uncaring, these complete pragmatists agonize over the right and wrong of what they've done, even if they feel there was no choice.

Interestingly enough, these six also share a belief that a Palestinian state should have been a priority, linked to a kind of disdain for Israeli politicians for not doing more to make it happen. "You knock on doors in the middle of the night, these moments end up etched deep inside you," Peri says. "When you retire, you become a bit of a leftist."

Israel's dilemma began in the aftermath of the Six-Day War, when 1 million Palestinians came under military rule overnight. "When the Arabs surrendered, we had no enemy," recalls Shalom, adding bitingly that when terrorism began, "it was lucky for us: We had work."

Always a controversial figure, even among fellow Shin Bet leaders, Shalom was brought down by 1984's Bus 300 incident. Two Palestinians hijacked the bus from Tel Aviv to Ashkelon. They were captured, interrogated, and then, in an action that caused a huge furor, summarily executed. "We killed them with their hands tied," Ayalon says, still furious.

Shalom talks reluctantly about this incident and clearly feels betrayed by the political establishment. But on one point he is immovable: "With terrorists, there are no morals. In the war against terror, forget about morality."

Not all terrorists, the gatekeepers take pains to point out, are Palestinian. In 1984, Shin Bet arrested militants who came to be known as the Jewish Underground. These men were caught red-handed placing bombs on Palestinian buses in Jerusalem that would have killed hundreds. But because of their political connections to the heart of the Israeli establishment, the perpetrators served minimal prison terms.

The only prime minister credited by the Shin Bet leaders with sincerely believing in a Palestinian state was Yitzhak Rabin, who signed the historic Oslo Accords with Yasser Arafat in 1993 that led directly to perhaps the film's most disturbing section, its examination of the murder of Rabin by an Orthodox Jewish assassin.

"The Gatekeepers" uses expertly selected newsreel footage throughout its length to counterpoint its interviews, and this is especially effective in putting on screen the horrific ways settler activists fomented hatred against Rabin. The interviews with Carmi Gillon, who was the head of Shin Bet during this time, are especially wrenching.

"He changed history, big time," Gillon says of the assassin. "Until today. It gets worse."

'the gatekeepers'

* * * *

Rating: Not rated
Director: Dror Moreh
Running time: 1 hour,
37 minutes