William Friedkin's The French Connection is an iconic '70s thriller for many reasons, including the chase between a commandeered car and an elevated train roaring above the streets of working-class Brooklyn, a full-throttle action scene still celebrated for its kinetic energy today.
But what makes this grimy procedural unique is Gene Hackman's "Popeye" Doyle, the morally compromised detective hunting drug dealers in a falling-apart New York City. Doyle isn't a corrupt cop, no. He's not on the take, nor is he phoning it in. He's a racist and a fanatic—he's married to the job.
But he's an incompetent cop and dangerous. Americans only see in black-and-white, even if the picture is in technicolor: we like our cops honest or crooked. Doyle is neither, he's just a hot-headed screw-up, a wreckless idiot. His partner, played by Roy Schneider, is a better lawman who enables Doyle, which is how it is.