The true story of Whitey Bulger, the brother of a state senator and the most infamous violent criminal in the history of South Boston, who became an FBI informant to take down a Mafia family invading his turf.
The general outlines wouldn’t seem to promise anything like that sort of experience, and Jez Butterworth and Mark Mallouk’s screenplay sometimes treats its flashback structure (articulated through FBI interrogations of key Bulger associates) as an excuse to tell, even summarize, rather than show. Testimonials become voice-over narration that papers over holes in the chronology. We meet Bulger and two powerful people who shield and enable him: his senator brother William “Billy” Bulger (Benedict Cumberbatch) and his childhood friend turned FBI agent James Connolly (Joel Edgerton). We watch as Connolly hatches a plan to pay back Bulger, who protected him when they were kids, by helping the gangster inform on the Italian mob that’s muscling in on his turf—essentially offering up the FBI as Bulger’s unwitting private army, waging war on rivals. We meet Bulger’s doting girlfriend Lindsey Cyr (Dakota Johnson) and his adorable son, Douglas Cyr (Luke Ryan), and of course Bulger’s criminal gang; their ranks include Jesse Plemons, Rory Cochrane, and the great W. Earl Brown, who’s turning into the Warren Oates of modern urban potboilers. All of the performers are superb and have at least one indelible moment, but remain rather undefined as individuals. They fade in and out of the story willy-nilly, and sometimes when one of them shows up again you’re surprised to see him because you forgot he was still alive. The sole exception is Peter Sarsgaard, whose supporting turn as a jumpy cokehead sums up a man’s pathetic life in just four scenes.
There are moments where you may wonder if the film’s mostly dour tone is a mistake. Bulger’s arrangement with the FBI—enabled by his lapdog Connolly, who thwarts testimony and fudges evidence to keep his pal from getting prosecuted—seems so transparently a con that you wouldn’t believe it went on for years unless outside reading confirmed that yes, indeed, this is how it happened. The staggering incompetence this film attributes to Boston’s bureau of the FBI suggests that Cooper and company might’ve missed the boat by not turning “Black Mass” into a black comedy about how easy it is to corrupt institutions from within. (Kevin Bacon’s performance as Connolly’s incredulous superior feels more comic than dramatic; on some level he knows what kind of con is being run and can’t believe how hard it is to prove it.) Still, you get a taste of that fundamental absurdity as the film drifts along—particularly through Connolly. He’s one of the great weasels in movie history, and in some ways a more disturbing character than Bulger, because he pretends to be a good guy.