On the Basis of Sex is one of those biopics released at the height of a long-public subject’s popularity. In this film’s unfortunate case, it also corresponds to a much more thorough, emotionally involving documentary that makes this narrative approach on the subject superfluous.

The subject in question is Supreme Court Justice Ruth Bader Ginsburg, whose leftward politics and belief in legal equality across the gender spectrum (and outspoken half-century career defending it) have made her a heroic figure during the Trump era. The documentary was 2018’s RBG, which made its way onto many Top 10 lists with its thorough, empathetic look at Ginsburg’s life, career and foundational relationship with her late husband, Martin. On the Basis of Sex treads similar ground, introducing Ruth (Felicity Jones ) and Martin (Armie Hammer) as two beautiful young legal fighters, following Ruth from college to their first big court win.

Director Mimi Leder and writer Daniel Stiepleman can’t really shoulder any blame for condensing as much of Ginsburg’s ethos into this small portion of her life. A biopic can’t shoulder the breadth of a documentary (and those that try — most recently Vice — often fall on their ambitions). Leder’s direction of the sequences in which Ginsburg stands up to court justices and precedents are straight from high-quality legal dramas and the only time in which On the Basis of Sex feels alive. But Leder and Stiepleman have trouble with the most essential part of the film, which is the relationship between Ginsburg and Martin. For whatever reason it just never lands, never feels natural.

Really, that unnaturalness is an ongoing issue with On the Basis of Sex. The aforementioned legal sequences are good, but the material connecting them feels like a checklist of moments from Ginsburg’s early life, replete with different men reduced to caricatures of cackling villains determined to stop her. Which, shit, it’s not like their attitudes are incorrectly depicted, but the beat-to-beat drama of the movie just lacks an engaging thread. There’s something missing here. Martin, for instance, gets cancer. But the reality of the couple’s struggle through that time feels like a footnote. Her precocious daughter Jane (Cailee Spaeny) challenges Ruth’s feminism during the ’70s, but it feels forced.

It’s impossible to fault On the Basis of Sex for its flaws, which are largely inherent to the biopic. And it couldn’t have avoided the comparisons to RBG, as the two were largely developed in a similar vein. Jones is great as Ginsburg (I think she’s an underrated actress who deserves more to do), but if you want to learn about Ginsburg or simply seek a compelling romance. watch RBG instead.