No good can come to a dog in a hunting play, especially if the play is named after the dog. This much is obvious in the first seconds of Craig Wright’s provocative and nuanced dark comedy “Lady,” when headlights illuminate the blackness of Rattlestick Playwrights Theater and the young dog runs off.

“Lady, heel!” Kenny (Michael Shannon) yells, to no avail. It’s 5 a.m. in the fogbound woods somewhere in the middle of Illinois, and there’s no way the day is going to end well for Kenny and his dog. It probably won’t end well for Kenny’s hunting companions, either, but mortal danger of a different strain is to blame for the jagged, possibly unbridgeable rift that’s grown between Dyson (Paul Sparks) and Graham (David Wilson Barnes).

Kenny, Dyson, and Graham have hit early middle age, with 36 years of friendship stretching behind them and differences on politics — most urgently the Iraq war — threatening whatever they still have: decades of common history; heart-piercingly intimate knowledge of each other’s weaknesses and failures; a deep, even insistent concern for one another’s well-being; the ability to hate in the way it’s possible to hate only the people we love best.

All of which is to say, they’re toting a lot of baggage with them into the woods. And, of course, they’re armed.

Graham, a hawkish conservative Democrat, is in town from Washington, where his friends long ago helped to send him, Kenny with some inherited money and Dyson by managing his campaign for Congress. “Those were different times,” Dyson says, furious now that Graham has morphed into someone whose principles he abhors, and genuinely frightened for his son, who listened to Graham talk last night at the Elks Club and promptly announced he was joining the Marines.

“He’s 18 years old,” Graham tells the seething Dyson. “He’s a grown man.”

“Eighteen in America is not a grown man,” Dyson snaps. “Eighteen in America is you’re really good at PlayStation and you like to f—.”

As pointed as the debate gets, this is not a left vs. right, red vs. blue play. Nothing — not in the men’s politics, not in their personalities, not in their friendship — is as clear-cut as that. Dexter Bullard’s fine production and excellent cast make sure of it.

Kenny, a politically apathetic slacker, is a kindhearted family man, sentimental enough to be proud of his friend the congressman no matter what. He’s also stoned in the early morning off his dying wife’s medical marijuana and has a disconcerting tendency to confuse movies with reality. Dyson, a professor, is not exactly a liberal, despite his moral outrage over the war; and for all his pain at his son’s decision, he’s not been as attentive a father as he could have been, in part because he devotes much of his time and energy to cheating on his wife. And the dispassionate, sometimes chilly Graham — whom Dyson, in an incongruously sweet remnant from childhood, calls Grammy even in the depths of his rancor — is solid in ways that his friends don’t even know.

Messrs. Wright (“Recent Tragic Events,” “Orange Flower Water”) and Bullard slip from drama to didacticism only once, when Dyson and Graham argue politics literally over Kenny’s head. This is bald metaphor, with Kenny standing in for the ignorant, unfocused American masses, always more concerned with personality than with policy. In an election season that finds the editor of Us Weekly, Janice Min, popping up in serious newspapers’ stories about political coverage, that peculiar American obsession is a relevant point, but “Lady” raises the issue with more craft elsewhere.

“I remember what matters,” the woolly-brained Kenny says early on, in self-defense. Even then, what he remembers — the list of facts he ticks off as evidence — is entirely personal. Funny thing, though: Dyson and Graham may look down on him, but they need him to keep their connection alive. Without the simple guy who sees something to love in each of them, even if he has to look to the past to find it, they probably wouldn’t even talk anymore.

Through September 28 (224 Waverly Place, between West 11th Street and Seventh Avenue South, 212-868-4444).