At a time when Americans are debating whether torture is acceptable in a democracy, I recommend an exhibition in Philadelphia by a group of young Israeli military veterans called “Breaking the Silence.”

On view at the Rotunda, the show consists of photos, films and discussions on the daily routines of soldiers in the occupied West Bank and Gaza. (You can read about it at www.breakingthesilence.org.il.)

This material is not about torture per se, but is a courageous examination of the boundaries any democracy must set for itself if it wants to remain true to its values.

The main goal, say the organizers, is to “expose the true reality in the (occupied) territories and as a consequence to promote a public debate on the moral price paid by Israeli society.”

“We want to force people to answer the tough questions we have in front of us, and to ask what are our moral boundaries, our red lines,” said Yehuda Shaul, 25, a chunky, bearded veteran who served two years in the West Bank. “We want people to examine their own value system and take responsibility.”

The exhibition grew out of the experiences of soldiers who served in the hotly contested city of Hebron between 2001 and 2004, during the Al Aqsa Intifada. The old town of Hebron contains the venerated Tomb of the Patriarchs, contested by Arabs and Jews. These days, the city’s heart is a ghost town, mostly shut by military order to protect a few hundred Jewish settlers living in a handful of buildings. The settlers often clash with the soldiers sent to protect them.

Any Palestinian trying to move through the old town, or pray at the main mosque, must pass through a series of checkpoints. Who gets stopped, searched and held for hours can be purely arbitrary.

Most of the soldiers in his brigade, Shaul says, believed at first that theirs was the most moral army, which could do “occupation with silk gloves.” Then the bubble burst. A series of photos, snapped by soldiers, shows the normal routine – described with captions or by guides at the exhibit. Soldiers running metal detectors over an old Palestinian woman. A cluster of smiling soldiers with blindfolded detainees. These may be Palestinians who broke the nightly curfew in trying to leave early for work; they will be left sitting on the roadside, handcuffed, for four to eight hours. The soldiers call it “drying them out.”

Checkpoints – there are hundreds on the West Bank – are a guaranteed source of humiliation. A film at the exhibit, taken by Israeli soldiers, shows a sergeant slapping around a hapless Palestinian at a checkpoint, with his child and mother watching. The sergeant explains he is setting an example. When the film was leaked to the press, the sergeant was jailed for six months; fellow soldiers protested that he was being made a scapegoat because such behavior happened all the time.

Over my years of covering the West Bank and Gaza, I have seen all sorts of behavior at checkpoints. But, Shaul says, occupation “instills total indifference in you. Questions pop up, and you find a way to go on.” He remembers manning a machine-gun post on a Hebron hill – a photo shows a Palestinian neighborhood spread out below. “They shoot, and then we shoot into several supposedly empty buildings.” The shooting is blind, and a one-minute pull releases 80 grenades. “No, we never knew what we hit. Questions are not something you have.”

But three to four months before his discharge, Shaul’s outlook changed. “The first moment you start thinking as a civilian, things you justified don’t apply.” In June 2004, 64 men from his unit made an exhibit of pictures they had taken. Now they are 500, and they speak across Israel of their personal stories.

I ask the obvious questions. Do you feel you are undermining Israel’s safety? “You could say that, if you subtract some things from a democracy, it would be safer,” Shaul replies. “I prefer a (real) democracy. You have to set red lines. There are some things you just do not do.”

And does he care whether or not Palestinians are doing similar soul-searching, say, about suicide bombers? He does not. “For me, Palestinians are a political issue. Israeli society is an existential issue.” Shaul begs the question of whether a political solution is possible.

“Breaking the Silence,” he says, “is about asking you to find your own red lines.” In 2007, he and other group members took more than 3,000 people, Israelis and foreigners alike, to Hebron to see for themselves the moral cost of occupation. They often were pelted with eggs or stones by settlers or even physically attacked.

But that hasn’t stopped Shaul from pressing his countrymen to look inward. At a time when President Bush is threatening to veto a congressional ban on the use of waterboarding by the CIA, we should be asking ourselves if our democracy is losing its moral boundaries. Such introspection is painful. But, as Yehuda Shaul knows, without red lines, it is very easy to get lost.