Then, abruptly, Rivers changed the subject, to a topic more divisive than class warfare or Woody Allen: Lena Dunham’s body. “Let me ask you something!” she said. “Lena Dunham. Who I think is, again, terrific. How can she wear dresses above the knee?” Stern said that what he loved about Dunham was that “she doesn’t give a shit.” “Oh, she has to,” Rivers insisted. “Every woman gives a shit.” When Stern and his co-host described funny scenes from “Girls” of Dunham in a bikini, Rivers nearly sputtered: “But that’s wrong! You’re sending a message out to people saying, ‘It’s O.K., stay fat, get diabetes, everybody die, lose your fingers.’ ” In a passionate rasp, she made her case. Dunham was a hypocrite for doing Vogue, she said, because it showed that she cared about being pretty. Stern was another hypocrite, for his “tits and ass” jokes, for his hot second wife—would he have married Dunham? Stern said that he thought Rivers would “rejoice” in the younger woman’s freedom. “But don’t make yourself, physically—don’t let them laugh at you physically,” Rivers pleaded, sounding adrift. “Don’t say it’s O.K. that other girls can look like this. Try to look better!”

The discussion felt oddly poignant: Joan Rivers’s reflexive emphasis on marriage and weight, her hard-bitten advice for surviving in a man’s world, seemed almost naïve in the context of Dunham’s fourth-wave-feminist exhibitionism. (Why would Dunham want to marry Stern?) The “Girls” creator was violating the rules that Rivers built her life on—was hemmed in by, protested, and enforced, often all at the same time. From the nineteen-sixties on, Rivers had been the purveyor of a harsh Realpolitik, one based on her experience: looks mattered. If you got cut off from access to men and money—and from men as the route to money—you were dead in the water. Women were one another’s competition, always. For half a century, this dark comedy of scarce resources had been her forte: many hands grasping, but only one golden ring. Rivers herself had fought hard for the token slot allotted to a female comic, yet she seemed thrown by a world in which that might no longer be necessary.

Like Moses and the Promised Land, she couldn’t cross over.