When Steve McQueen won the 2013 Academy Award for Best Picture for 12 Years a Slave, it was a testament to his choice of subject matter rather than his skills as a director. With a background in video art – a medium in which boring and pointless exercises often enjoy critical acclaim – McQueen has never seemed entirely fluent as a maker of feature films. With Widows he has taken a big step forward.

The story began life as a 2002 British TV mini-series scripted by the prolific Lynda La Plante. The new version has been transferred to Chicago, with a screenplay by Gillian Flynn in collaboration with the director. Flynn, best known as the author of mystery thriller Gone Girl (expertly filmed by David Fincher) has a touch of class about her writing. The dialogue in Widows is crisp and clever and the characters full of surprises. What could have been mere pulp is transformed into something far more sophisticated.

The plot may be inherently ridiculous but does it matter? It was pretty silly of Cary Grant to take off like a fugitive in North by Northwest instead of going straight to the police, but no one complains about Alfred Hitchcock's lack of plausibility. The trick is to keep viewers in a state of suspended disbelief until the credits roll. What they think afterwards, upon mature reflection, is no big deal.

We begin in the bedroom, with Veronica (Viola Davis) locked in an embrace with her rugged, pale-skinned husband, Harry (Liam Neeson). By the time those first scenes are over we've ascertained that Harry is a major crook who supports their lifestyle with the proceeds of crime. We move swiftly to Harry's next big job, which goes horribly wrong, ending in fiery doom for the four gang members. Veronica, now a grieving widow, finds she has a new problem on her hands when would-be politician and full-time gangster Jamal Manning (Bryan Tyree Henry) comes to call. It seems that the money Harry stole in his final heist was Jamal's election fund, and he would like it returned.

Trail of destruction

Viola has two weeks to find the cash or face the consequences. Judging by the trail of destruction left by Jamal's psychopathic right-hand man, Jatemme (Daniel Kaluuya), it would be a good idea to find the money. After coming across a secret notebook in which Harry meticulously planned all his capers, Veronica decides to carry out the next job. For her accomplices she enlists the widows of the men who worked and died with her husband. This means languid blonde Alice (Elizabeth Debicki) and feisty Latina Linda (Michelle Rodriguez). The other widow, Amanda (Carrie Coon), decides not to play along, and is replaced by Belle (Cynthia Erivo), an athletic black hairdresser who always seems to be running.

The plot is interwoven with a tale of dirty politics in the Chicago suburbs, with Jack Mulligan (Colin Farrell) set to succeed his father, Tom (Robert Duvall) as the local representative. Their chief opponent is Jamal, who stands a good chance of winning over the poor black neighbourhoods – but there are no good guys in this confrontation. Both sides are self-serving profiteers who'll do anything to succeed.

In this movie crime and politics are inseparable, with each new twist drawing them closer together. As we are all students of American politics nowadays it's impossible not to think of the vast sums spent on election campaigns, the constant friction over race issues, the attempts to deceive or discourage voters from minority communities, the stink of corruption that pervades the process. What might once have seemed exaggerated is now all too familiar.

Everyone's a criminal

Widows is driven by black and white relationships, from Veronica's marriage to Harry, to Jack and Jamal's political face-off. To their credit McQueen and Flynn have resisted the affirmative-action approach of making the blacks into heroes and the whites into villains. In this movie almost everyone is a criminal, either by choice or weight of circumstances. The black preacher who croons about love from his pulpit is also ready to sell his influence to the highest bidder. Alice's mother (a beautifully vulgar cameo by Jacki Weaver), encourages her to find work as an escort. When Jack feels like packing it all in, his innocent-looking girlfriend tells him to man up.

The film might still have ended in a cliché-fest if it weren't for the excellence of the cast, most notably Viola Davis as the determined leader of the gang, and Elizabeth Debicki as a passive woman who gradually finds her mojo. Robert Duvall is so good at playing cranky old bastards one wonders if he's really acting.

If the filmmakers appear to take a cynical or pessimistic approach to American politics, they offer redemption in the spectacle of a disparate group of women working together to achieve an apparently impossible goal. Their strength, as Veronica puts it in not so many words, lies in the fact that they are underestimated and overlooked. By pooling their skills and finding unsuspected resources within themselves they can beat the big-time male criminals at their own game. One suspects there's a message here for all those American voters who feel disenchanted and disenfranchised: "Don't accept an ever-declining status quo, take control of your lives, get organised and fight back."

Widows

Directed by Steve McQueen

Written by Gillian Flynn and Steve McQueen, after a novel by Lynda La Plante,

Starring Viola Davis, Michelle Rodriguez, Elizabeth Debicki, Cynthia Erivo, Colin Farrell, Liam Neeson, Robert Duvall, Bryan Tyree Henry, Daniel Kaluuya, Jacki Weaver, Lukas Haas, Carrie Coon, Molly Kunz

UK/USA, rated MA 15+, 129 mins