Usually, when people talk about establishing Holocaust memorials, they talk about commemorating the victims, or honoring their sacrifice by educating future generations about tolerance. But ask Robert Morgenthau, scion of one of New York’s most powerful Jewish families, why he decided to commit his time and energy nearly three decades ago to the establishment of a Holocaust museum in the city, and he’ll give you the answer you’d expect from a nine-term district attorney: “I thought it was incredibly important for people to know what happens when criminals take over the government.”Morgenthau, New York’s chief prosecutor, knows his criminals. But at 90, he plans to retire at the end of the year, having decided, apparently with some hesitation, not to seek reelection to a 10th term in the office he’s held since 1975—just as the museum he helped found, and still chairs, known as the Museum of Jewish Heritage, is mounting a retrospective of Morgenthau’s public career alongside that of his grandfather, who served as President Wilson’s ambassador to the Ottoman Empire during the First World War, and his father, who was President Roosevelt’s Treasury secretary during the Depression and the Second World War. (Museum director David Marwell said the exhibit was planned to open after the November election, just in case Morgenthau had decided to run again, and the typically shy prosecutor said he didn’t see it until after it was installed.)Titled ”A Legacy of Service,” the show explores the influence the Morgenthaus held over the fate of Jews in the 20th century—in Palestine, in Europe, in Israel, and as refugees in America—despite the family’s assimilationist ambivalence about religious observance and ethnic identity. “If someone asked what religion I was, my mother told me to say I was American,” recalled Morgenthau’s elder brother, Henry Morgenthau III, a former public television producer and the author of an autobiography, Mostly Morgenthaus, that traces his own return to faith through his marriage to Ruth Schachter, a Holocaust survivor and Orthodox Jew.The first item in the exhibit is a ledger Henry Morgenthau Sr., kept as a young man to log various ethical infractions, from slander to vanity, inspired by William Penn’s Quaker handbook No Cross, No Crown; the effort dovetailed with visits he made to churches of various denominations, to hear firebrand preachers including Henry Ward Beecher. The second is a silver menorah Morgenthau Sr. acquired in Palestine in 1914—by which time he had made a fortune in real estate and served as the founding president of Rabbi Stephen S. Wise’s Free Synagogue, an egalitarian institution intended to be “pewless and dueless.” As Wilson’s envoy in Constantinople, Morgenthau Sr. famously pressured the Turks to halt the genocide of Armenians—arguing that it didn’t matter to him that their victims were Christian and not Jewish—but he also moved quickly to assist Jewish settlers in Palestine after war broke out in August 1914, sending a cable to the Jewish philanthropist Jacob Schiff in New York requesting $50,000 in loans to prevent “serious destruction” in “thriving colonies.” The telegram elicted a swift reply from Schiff assuring Morgenthau Sr. he would convene an emergency meeting of the American Jewish Committee, or put up the cash himself.But after returning to America, Morgenthau Sr. publicly turned away from the Zionist cause. In 1921, he wrote a broadside in the monthly World’s Work, which was quoted extensively in the New York Times, asserting that Zionism was “the most stupendous fallacy in Jewish history.” America, he argued, was where Jews had found their true Zion. “If I were pressed to define myself by any single appelation I would unhesitatingly select the one word ‘American,’” he wrote. “We in America refuse to set ourselves apart in a voluntary ghetto for the sake of old traditional observances.” Yet less than 20 years later, even as his son was sitting at Roosevelt’s right hand at the Treasury, helping implement the New Deal that Jewish voters overwhelmingly backed, the elder Morgenthau found America’s doors closed to his increasingly desperate Jewish relatives who were trying to flee Germany. In 1939, the same year Morgenthau Jr. failed to help secure U.S. entry for nearly a thousand Jewish refugees aboard the ship S.S. St. Louis, who were were returned to Europe after being denied landing in Cuba, Morgenthau Sr. succeeded in helping dozens of cousins win visas by providing affidavits pledging financial support.One of them, Sophie Kahn, is pictured in the exhibit, a smiling 10-year-old on the train platform in Stuttgart, standing with her older brother and father. (Her mother had passed away from a chronic kidney ailment two years before, freeing her father to aggressively seek emigration papers for the family.) Morgenthau Sr., then 82, invited the family to his Fifth Avenue apartment; Kahn (now Taub) recalled dressing in her Shabbat best and being anxious about how to refuse if he offered her non-kosher food. “We were flüchtlings,” she said, using the German word for refugee. “But he was wonderful—he only gave us fruit, so there was no problem.” Every fall, she said, her father would send Morgenthau Sr. greetings for the Jewish New Year; after Morgenthau Sr. died, in 1946, her brother, an Orthodox rabbi, recited Kaddish on his behalf, as he would for a parent.Yet, Morgenthau Sr.—who told his grandson, Robert, he regretted not getting into public service until he was 55—kept the whole business quiet from the rest of the family. “He never talked about it—I don’t even know if my father knew at the time,” Robert Morgenthau told Tablet. “When he died he had a list of 32 relatives in his desk he gave money to on a regular basis, but he never told any of us about it—the last couple of years he was worried about money, which I thought was strange, but I didn’t realize he had all these obligations.”Meanwhile, Henry Morgenthau Jr. was—perhaps belatedly—fighting on behalf of European refugees. In 1944, his staff, led by Josiah DuBois, had produced a document titled “A Report to the Secretary on the Acquiescence of This Government in the Murder of the Jews” claiming the State Department had quashed details of the Nazis’ murder campaign; Morgenthau Jr. softened the headline to “Personal Report to the President” before forwarding it to Roosevelt, who agreed to the establishment of the War Refugee Board, which succeeded in saving as many as 200,000 Jews. “I don’t think it was guilt,” said Andrew Meier, a journalist who is writing a biography of the Morgenthau family. “But it was a moral obligation for him.”After the war, devastated by the deaths of both his parents, his wife, as well as of Roosevelt, Morgenthau Jr. committed himself to reversing his father’s anti-Zionist stance and fundraising on behalf of the new Israeli state. The exhibit includes audio of Morgenthau Jr. fundraising for the United Jewish Appeal; he befriended David Ben-Gurion and, according to Meier, even considered becoming Israel’s first finance minister. At the same time, though, he remained committed to America, delivering a speech in 1948 at Yeshiva University in which he insisted “the Jew who is true to his faith and to his people will be true to America.”The current generation of Morgenthaus espouses varying degrees of Jewish identity; some are practicing Christians, while other children identify as Jewish. “There was a time when the family had to suppress its Jewishness in order to open doors, and that’s not true any more,” said Ben Morgenthau, the older son of Henry Morgenthau III, a pediatrician in San Francisco who considers himself Jewish. Yet all of them consider themselves wholly Morgenthaus. “This is a family with unusual continuity in terms of their involvement in the public world as well as a certain inevitability, given the numbers of Jews in the United States and what was going on in the world at the time—the Jews were at the center of all of it,” said Moses Rischin, an emeritus professor of history at San Francisco State University. “But there was a tremendous generational break, in terms of Robert Morgenthau’s role—it really is a different world.” Today, Rischin argued, “there is no public role of being a Jew, unless you’re a rabbi—you’re identified by your profession.” Accordingly, the last section of the exhibit portrays Robert Morgenthau as a Navy veteran and public servant devoted to redressing pervasive social ills, like sexism and racism. (The show includes a letter of thanks from new Supreme Court justice Sonia Sotomayor, who worked for Morgenthau in the early 1970s.)Morgenthau, too, sees himself that way, though he also has a record of pushing for the return of art looted by the Nazis; during a visit to the museum, he said he plans to devote himself to lobbying for immigration reform after he leaves office at the end of the year. Yet, at the opening of the exhibit on Sunday, surrounded by multiple generations of Morgenthaus, he described his first, and only, visit to the family’s ancestral home in Mannheim, Germany, in 1991—a trip he made despite his father’s admonition decades earlier to avoid the country at all costs. “I figured by then it was safe,” he joked. With his youngest son and eldest grandson, he toured the old Jewish cemetery and other landmarks. “And, you know, I wasn’t wearing my Star of David, but when we got ready to leave, the porter said, ‘Well, I guess you’ll be flying El Al,’” Morgenthau recalled, sardonically. “So, you’ve got to know where you come from. That’s all it is.”Allison Hoffman is a senior editor at Tablet Magazine. Her Twitter feed is @allisont_dc.