Like a Bad Lieutenant minus the moral and spiritual crises, rural Ireland's Sergeant Gerry Boyle (Gleeson) shrugs off crime, drinks and drugs while on duty, and enjoys the fine company of role-playing whores (two at a time, thank you very much) in The Guard, John Michael McDonagh's caustically funny riff on cop and crime films. Boyle is introduced not caring about some reckless kids who fatally smash up their car (except, of course, for the narcotics in one of their pockets), but he's forced into action when his newbie city-transplant partner McBride (Rory Keenan) goes missing shortly after they find a man murdered. Upon FBI agent Wendell Everett's (Don Cheadle) arrival, both crimes are linked to an impending drug shipment and Boyle teams with his American superior, a familiar pairing of a fish-out-of-water foreigner with a seasoned local vet that McDonagh repeatedly tweaks.
With shrewd wit, McDonagh's script proceeds to self-reflexively address the very conventions it's employing, be it the exaggerated Lethal Weapon-style wild-man Caucasian/straight-laced African-American central dynamic, the trio of highly educated and courteous baddies, or an officer asking "Is it all there?" about his pay-off money, a stereotypically suspicious query that Mark Strong's English trafficker slams as making no sense, since skimming money off the top of a bribe would defeat the transaction's entire purpose.
Boyle's jabs at America and African Americans amusingly straddle the line between racist cluelessness and shrewd needling—or, as Everett tells Boyle, "I can't tell if you're really motherfucking dumb or really motherfucking smart." More fundamentally, such jokes speak to the U.S. cinematic lineage to which The Guard is indebted and with which it wants to screw, with the nominal investigation plot proving perfunctory and cop clichés—via discussions of the term "APB," or the townsfolk's eagerness for Everett to be from the FBI's hallowed "Behavioral Science Unit" (and oozing disappointment when they hear he's only interested in narcotics)—regularly introduced in half-mocking tones.
McDonagh's direction is smooth, but it's his writing that carries the day, treating genre elements with both seriousness and subversive humor, all while fashioning the borderline-caricature Boyle with enough actual humanity (primarily through his honest rapport with his dying mom) to keep the proceedings from devolving into total frivolous jokiness. The Guard, however, is ultimately Gleason's show, and even if his protagonist's naughtiness is eventually revealed to be something of a façade, the star—whether messing with straight man Cheadle, or flashing a brand of heroism born from a combination of simple pragmatism and interrupting-my-drug-fun annoyance—turns his bastard-with-a-heart-of-gold into a hilarious comedic creation, and one deserving of his final, cheekily meta-ish fate.