“Widows” probably works best as a three-minute trailer (punchy and funny) or a longform miniseries (deep and complicated). It’s a movie, though, which means we’re stuck with a fitfully engaging, 129-minute feature that only occasionally gets out of gear.

The film is actually based on a miniseries, broadcast in England in the 1980s. Adapted here by “Gone Girl” writer Gillian Flynn and director Steve McQueen, “Widows” tries to be a lot of different things: heist thriller, feminist statement, social-issue diagnosis. That’s a lot to bite off, and 129 minutes isn’t enough time for proper chewing.

We begin with a crime that goes wrong, resulting in the deaths of three accomplished Chicago crooks. Their widows, played by Viola Davis, Elizabeth Debicki and Michelle Rodriguez, are threatened by unhappy gangsters whose money is missing in the aftermath of the spree. If the women don’t band together and steal an equivalent amount, their odds of survival are slim.

Meanwhile, a slick candidate (Colin Farrell) seeks to replace his deeply corrupt father (Robert Duvall) as alderman. The opposing candidate (the deliciously menacing Brian Tyree Henry) is hardly better than the entrenched politicos, especially as represented by his brutal henchman (Daniel Kaluuya, from “Get Out”).

McQueen, the guiding hand behind “12 Years a Slave,” captures some striking moments. A scene with a dog used as a not-so-subtle warning is extremely unnerving. And there’s a very eccentric shot, of the outside of a car, depicting exactly how quick it takes to get from the ghetto to the poshest street in town.

As an action movie, “Widows” lacks gusto, and its political awareness has been done better on TV. It’s curiously unbalanced, too. Viola Davis (potent as always) plays the central figure, but we also see a lot about Debicki’s anxious character, forced to consider a career in high-class sex work with a rich client (Lukas Haas). Yet the other widow, Rodriguez, gets no personal life after her introduction.

And we’d like to know more about the babysitter who becomes a member of the gang, played by livewire Cynthia Erivo (late of “Bad Times at the El Royale”). She has a great moment, sprinting for a bus, that puts to shame the impressive supercuts of Tom Cruise running — because she’s running out of desperation, not heroism.

Debicki, a towering presence (literally — she’s 6-3) in the “Guardians of the Galaxy” world, is the breakout star from this ensemble. It’s a good cast, with tasty bits from Liam Neeson (as Davis’ late husband), Carrie Coon and Jacki Weaver.

All the elements are there, yet “Widows” doesn’t really satisfy. The people are vivid, the situations intriguing, but the movie leaves you wanting more — and not in the good way.

“Widows” (2½ stars)

The widows of a group of crooks band together to steal money their husbands owed to the mob — a premise that doesn’t entirely work as a crime thriller or a social-issue diagnosis. Good cast, though, even if the whole thing leaves you wanting more. With Viola Davis, Elizabeth Debicki, Liam Neeson, Cynthia Erivo.

Rating: R, for violence, nudity, language

Showing: Alderwood Mall, Everett Stadium, Galaxy Monroe, Marysville, Meridian, Oak Tree, Pacific Place, Thornton Place, Woodinville, Cascade Mall