They have assassinated Palestinians, incarcerated thousands and disrupted the lives of many thousands more - but they have become the most persuasive advocates in Israel for peaceful relations with an independent Palestinian state.
In a remarkable documentary The Gatekeepers, short-listed for best foreign documentary at the upcoming Academy Awards, Israeli film-maker Dror Moreh interviews six former heads of the Israeli Shin Bet security service.
They are unapologetic for the harsh steps their job has called for in suppressing Palestinian uprisings and suicide bombings. But all condemn the political level for failing to take advantage of the periods of relative tranquillity, like the present one, to seriously pursue a political accommodation. Their ire appears to be directed particularly at Prime Minister Benjamin Netanyahu.
"We win every battle but we're losing the war," said Ami Ayalon, 67, a decorated war hero who headed the Shin Bet between 1995-2000. As a child, he was told by his parents that in Jerusalem there was a building with a long corridor on the second floor, which led to a door behind which sat a wise man thinking about what the people need. "I reached that corridor [leading to the Cabinet room] but there was no door and no wise man."
Avraham Shalom, 85, said that after the Six Day War he and others favoured the creation of a Palestinian state. "But then the terror started and we were so busy fighting it we forgot about the Palestinian state."
