A documentary by Julie Cohen and Betsy West. Rated G

In the old days, only the most engaged Americans knew the names and faces of Supreme Court justices. (And cabinet members, White House lawyers, and chiefs of staff.) But now, millions look to identify allies and enemies during a giant nation’s fast race to the bottom. In the case of Ruth Bader Ginsburg, profiled in this straightforward doc, there’s also a chance to find some living continuity with the better parts of the past.

Now 85, she’s been on the big bench for 15 years. But Ginsburg had several lives before that, all dedicated to quietly pushing against entrenched barriers. The title here, playing on the Notorious B.I.G., nods to her late-life conversion to overt feistiness, as seen in her workout footage (sweatshirt: “Super Diva”) and low-key embrace of rap-style fame.

Having been born at the start of the Great Depression, she has been consistently demure, if persistent, in her trailblazing. Only the second female justice appointed to the Supremes, she was one of nine women in a class of 500 men at Harvard Law School, where she became the first woman on the Harvard Law Review. This connects her with Barack Obama, just as her most despised foe, red-baiter Joseph McCarthy, is connected to the current president through his legal counsel Roy Cohn, Trump’s moral and political mentor.

The theme of two Americas—one aspirationally democratic, the other crudely authoritarian—runs through the film, but it’s not articulated by Ginsburg or interrogated by directors Julie Cohen and Betsy West. “I tend to be more sober,” the subject admits, and indeed friends and family members don’t describe kidding around, or self-revelation, as among her qualities. But seriousness has centred her long career, and keeps her working at a time of peril. (She almost retired during Obama’s tenure, but now would be replaced by a Scalia-type reactionary.)

Structured around the brief autobiography she read at her own confirmation hearing, the well-paced movie touches on all that, if only lightly. But it’s also a surprisingly touching love story, starting at Harvard, where she met and married Marty Ginsburg. They pushed and carried each other through school, sickness, parenthood, and legal eminence from 1956 until his death in 2010. Whenever his name comes up, you see a notorious twinkle that’s otherwise absent.