Claude Lanzmann’s new film, “The Last of the Unjust,” diagnoses a present-day moral and political crisis regarding the use of power, the essence of freedom, and the nature of responsibility. It’s centered on interviews that Lanzmann filmed in 1975 with Benjamin Murmelstein, who was an Elder of the Jews in the Potemkin-village concentration camp of Theresienstadt. The Elders were Jewish community leaders whom Nazi overlords forced, under close and menacing supervision, to administer ghettos and concentration camps. Murmelstein (who had been a leading rabbi in Vienna) was the only Elder to survive the war. Many Jews considered him a traitor, a collaborator, for his work under Nazi authority.

The interviews with Murmelstein were the first that Lanzmann filmed for the project that would ultimately become “Shoah.” He didn’t include any of the footage of Murmelstein in “Shoah,” and Murmelstein’s name isn’t mentioned there. Yet “The Last of the Unjust” is utterly continuous with “Shoah,” and the questions that Lanzmann addresses directly in the new film were, from the start, central to that epochal film.

There’s an Elder of the Jews who appears, virtually, in “Shoah”: Adam Czerniakow, who was put at the head of the Jewish Council in the Warsaw Ghetto. Czerniakow kept a diary during the war; Lanzmann refers to it in an interview with a former Nazi official, and the historian Raul Hilberg speaks of it in detail with Lanzmann, explaining that Czerniakow attempted to maintain the illusion of a future in the ghetto with such activities as “chess tournaments … a theatre, a children’s festival.” But as the pace of deportations from the ghetto to the death camp of Treblinka accelerated, and when he saw that his efforts to protect his fellow Jews (and, especially, children) from the Nazis were in vain, he committed suicide.

In “The Last of the Unjust,” Murmelstein explains that, after the war, when he was being interrogated by Czech authorities, one official asked, “How come you’re alive?” Murmelstein’s retort was in kind: “How come you’re alive?” The very fact of Murmelstein’s survival was held against him; if he had managed to get through the war, it must have been because he had carried out the orders of the Nazis to their satisfaction. He had been forced to organize deportations from Theresienstadt to what he thought of solely as “the east” (but which, as he learned near the end of the war, was Auschwitz), and it was as if his own survival was the reward for this diabolical bargain.

That broad brush of moral assumptions fails to consider both the mechanism of Nazi rule over all and the specific role that Theresienstadt, the show camp, served within it. What emerges in Murmelstein’s testimony is the virtual sword of Damocles hanging over the heads of the Elders (as there was over the head of any concentration-camp inmate). In one of the most agonized scenes in the film, Lanzmann, in a courtyard in Theresienstadt, cites and reads aloud from excerpts from Murmelstein’s own 1961 book about Theresienstadt regarding the execution of Jews by hanging that took place in that very courtyard. Lanzmann cites the Nazi commander’s order that the Elder in nominal charge, Jakob Edelstein, find a hangman from among the Jewish inmates, and the defiant response to the executions that followed—the chanting of the Kaddish (the Jewish prayer for the dead). (Edelstein and his successor, Paul Eppstein, were both killed by the Nazis; it was after Eppstein’s death that Murmelstein was forced to succeed him.) The very reign of terror that prevailed in the camps, the constant and unremitting threat of death for Murmelstein and for all the Jews of Theresienstadt, is the ambient subject of the movie. (Writing here last fall, I likened that reign to the depictions of masters’ absolute power of life and death over their slaves in “12 Years a Slave.”)

For Murmelstein, the maintenance of the illusion that the Nazis intended to foster—the public image of Theresienstadt as a decent place for Jews to live—was essential to the survival of the camp’s Jewish inmates. As long as he could help to maintain the illusion, the lives of the Jews interned there were of value to the Nazi regime—and so Murmelstein threw himself into the tasks at hand, whether using his authority to contain an outbreak of typhus (which could have been used as an excuse to liquidate the camp), to oversee the physical “beautification” of the camp, or to help in the production of a propaganda film (excerpts of which Lanzmann shows) that depicted the purported normalcy of life in Theresienstadt.

These matters find painful, surprising premonitions in “Shoah.” Two of that film’s most exalted witnesses are Filip Müller, a survivor of Auschwitz, and Abraham Bomba, a survivor of Treblinka. Müller was a member of the Sonderkommando, the special detail that was responsible for getting deportees into the gas chambers and then getting the corpses out of them. Bomba, a barber in his hometown, was part of a detail that cut the hair of prisoners in the gas chamber itself, moments before their murder. Both Müller and Bomba were required to maintain utter secrecy about the imminent fate of those who were entrusted to them; they helped to deceive the prisoners who were about to die, to maintain the illusion that the chamber was actually a disinfection site, a shower room where they were about to be cleansed to help keep them healthy. Here’s what Müller said: