Betye Saar, now 92, has been making important and influential work for nearly 60 years. Yet no big New York museum has given her a full retrospective, or even a significant one-person show, since a 1975 solo at the Whitney Museum of American Art. As the New-York Historical Society’s exhibition “Betye Saar: Keepin’ It Clean” demonstrates, the institutional oversight is especially baffling, as her primary themes — racial justice and feminism — are exactly attuned to the present moment and, indeed, to every American moment within memory.

Ms. Saar grew up in the Watts section of Los Angeles, watching the immigrant Italian artist Simon Rodia construct his fabulous towers from scrap materials. An encounter with Joseph Cornell’s art in the early 1960s convinced her that assemblage could be intimately scaled and politically pointed. By then, she was already involved in the Black Arts and women’s movements. Her 1972 breakthrough piece, “The Liberation of Aunt Jemima,” merges the two by transforming the racist stereotype of the smiling black mammy into an armed freedom fighter.

In the show at the New-York Historical Society, which comes from the Craft & Folk Art Museum in Los Angeles, the same figure appears, though the main transformed element is different: the old- fashioned wooden washboard, once a domestic staple and now an antique artifact. Generations of women, among them servants, used it to keep things clean , though without being able to erase the stains of racism and sexism from their lives. But in the present of Black Lives Matter and #MeToo, the struggle to do so goes on . “Extreme Times Call for Extreme Heroines” is the title of a work in the show. Someone should alert the major art museum on the opposite side of Central Park that there’s one such heroine here. HOLLAND COTTER

Through May 27. 170 Central Park West; 212-873-3400, nyhistory.org.