In 1958, David Ben-Gurion sent a letter to fifty Jewish leaders around the world, asking, "Who is a Jew?" He had good political reasons to launch such an inquiry, and equally good reasons to expect answers or attempts at answers. Isaiah Berlin wrote back, and so did the Jewish scholar Alexander Altmann, the novelist S.Y. Agnon, and the Lubavitcher Rebbe, as well as many others. But Abba Hillel Silver, the prominent Reform rabbi and American Zionist leader who had represented the Jewish Agency before the United Nations a decade earlier, did not respond to Ben-Gurion's missive—not directly, anyhow.