You may expect a political biography to at least somewhat involve, you know, politics.

Alas, that’s not quite the case with The Iron Lady, Phyllida Lloyd’s portrait of former British Prime Minister Margaret Thatcher. It’s a story about a woman remembering past triumphs and sacrifices. It’s a story about a trailblazer who punched through a glass ceiling. But it’s not a story about Thatcher’s political leanings and important dealings, except in the most cursory way.

When the film opens, we see Thatcher (Meryl Streep) as a doddering old woman out buying milk. Over breakfast, with her husband, Denis (Jim Broadbent), she complains about the milk’s price. When her daughter (Olivia Colman) chastises her for leaving the house on her own, Thatcher brushes her off as the stubborn elderly do, exclaiming in a very English way, “I’m not for the knackers yet!” (The melodious screenplay is by Shame scripter Abi Morgan.) Ah, but she is: Denis is dead, and Mags has a rather serious case of dementia, not only hallucinating but often unable to separate past from the present.

Which makes for a very convenient storytelling gimmick, a framework nearly identical to that of another recent political biopic, J. Edgar. But The Iron Lady’s old-age makeup isn’t horrendous and distracting, and Morgan doesn’t muddle the plot—mostly because she brushes over the thinky bits in favor of sentimentality. If you’re not familiar with Thatcher’s politics, you won’t learn about them here; labor strife, the Falklands conflict, and the Cold War are only touched on (often within Thatcher’s nightmares) before we’re whipped back to the poor-old-biddy present.

The aspect of Thatcher’s life and career that is emphasized instead is her inarguable ballsiness. This is a woman who knew from a very young age who she was and what she wanted to be (the youthful Thatcher is played by Alexandra Roach). She flashes her steely will at every opportunity, from Denis’ marriage proposal (“I cannot die washing up a teacup!”) to demanding a pen with which to correct a document during a cabinet meeting (her exasperation and fingersnaps are reminiscent of Streep’s Sister Aloysius in Doubt). The character of the character is nearly enough to compensate for the film’s historical voids and occasional old-age treacle.

But most crucial to The Iron Lady’s success is, of course, its star—and Streep delivers as you’d expect her to. The expert hair and makeup help, but Streep’s got the essence and obstinance of Thatcher down. She wears the woman like a second skin, with her voice in particular at once affected and sounding natural (as natural as Thatcher could sound, at least). It’s a guaranteed Academy Award nomination for the perennial Oscar contender—and a performance you’ll likely admire a bit more than the movie itself.