Starring Mark Wahlberg. Rated 14A.

In these precarious times, it might not seem, well, helpful to put out a movie celebrating the trouncing of Muslim terrorists by American law enforcement—let alone one that turns such a heinous act of human carnage into entertainment.

The nationalistic title, in the same oversimplified, rah-rah vein as such other Peter Berg–Mark Wahlberg directing-acting vehicles as Lone Survivor and Deepwater Horizon, doesn’t suggest the complexity such a project would require, either.

But damned if Patriots Day doesn’t achieve an intensity and gritty, jittery-handheld authenticity that will have you riveted even if you think you remember the details of the four-day manhunt that followed the Boston Marathon bombing.

The biggest surprise is the depth of some of its character portraits, most notably the conflicted Dzhokhar Tsarnaev (Alex Wolff, as the younger of two brothers who set the pressure-cooker bombs). He’s bullied and deeply conflicted, spouting doped-out-dude “yo”s and “bro”s when he’s not espousing 9/11 conspiracy theories.

And then there’s the film’s fascinating real hero, Dun Meng (Jimmy O. Yang), the affable Chinese immigrant whose new Mercedes SUV was hijacked by the duo, and who risked his life to get the word to cops.

Director Berg has gone into meticulous detail in researching and restaging the events that led up to and followed the bombing, even integrating the real surveillance video investigators used to so quickly piece together the case. Cutting frantically back and forth between the brothers’ domestic hideout, the huge warehouse on the Boston docks the FBI turns into its brain centre, and the emergency rooms where doctors struggle to save limbs, Berg achieves a breathless timeline.

There are problems. Wahlberg’s fictional cop, Tommy Saunders, who at least is a humorous antihero with a bum knee here, manages to be in too many convenient places. The clichéd turf battles between law-enforcement levels lead to too many shouting matches. And this is a shamelessly masculine world, with the women reduced to the role of passionately supportive wives.

Overall, though, Berg’s managed to do the impossible: he crafts a respectful portrait of the Boston citizens who pulled together in the face of trauma while he creates a taut, electric action movie. Just don’t expect Patriots Day to change the world or anything.