Ewan McGregor is a versatile and durable actor who has spent a lot of time on film sets, and someday he might become an accomplished filmmaker, but his feature directorial debut is one of the most unfortunate literary adaptations in recent memory.

McGregor directs and stars in the ponderous, stagey-looking, emotionally uninvolving, unpleasant and often shrill “American Pastoral.” Somewhere in the translation from book to film, we lose most of the memorably heartbreaking elegance and deep insight of Philip Roth’s Pulitzer Prize-winning Broken American Dream novel about a former high school golden boy whose seemingly sure path to an idyllic life is shredded by domestic strife and the social unrest of the 1960s.

Nearly everything about “American Pastoral” is ill-conceived, including the miscasting of McGregor as Seymour “Swede” Levov, a Jewish former high school football hero in post-World War II New Jersey. As portrayed by McGregor, Swede is a sincere but often clueless dupe who seems to be the last person in his world to realize what’s happening. He’s forever RAISING HIS VOICE in happiness, astonishment, bewilderment, anger or frustration.

When Swede is in his early 20s and America is basking in the unbridled optimism of the late 1940s-early 1950s, he appears to be on track for a life worth envying.

All the pieces are in place.

Swede marries a beautiful shiksa pageant queen aptly named Dawn (Jennifer Connelly), who gives birth to their equally aptly named daughter, Merry. He takes over the day-to-day operation of his father’s successful glove factory in Newark. (Peter Riegert gives the warmest and most believable performance in the film as Swede’s father.) And he sets up the family in a beautiful country home on a sprawling patch of land in Rimrock, New Jersey. Why, there’s even room on the rolling farmland for a couple of cows who are treated like pets.

Swede and Dawn dote on the precocious Merry, a brilliant child who battles a severe stuttering problem. (Hannah Nordberg plays the young Merry. Dakota Fanning plays her as a teenager and a woman in her 20s.)

But Merry is an ultra-sensitive child who feels isolated from other children because of her stuttering, and deeply, personally wounded by the injustices of the world. By the time Merry turns 16, it’s the late 1960s and she has become a full-fledged, self-appointed radical. The mere sight of LBJ on the family television is enough to send Merry into a raging, profanity-laced tirade — first directed at the president, and then at her parents, whom she has come to loathe for what she perceives as their oblivious, bourgeois values.

Merry’s radicalism turns into full-fledged anarchy. Early one morning, a bomb goes off in the neighborhood post office, an innocent man is killed — and Merry is identified as the prime suspect. She goes missing before the authorities can close in.

“American Pastoral” segues into a Cliff’s Notes version of the 1960s, brimming with superficial caricatures and worn-to-the-bone cliches, including the use of Buffalo Springfield’s “For What It’s Worth” — a great anthem for its time to be sure, but beyond tired as a storytelling device at this point.

Dawn tries to reinvent herself, complete with plastic surgery, while Swede becomes ever more obsessed with finding Merry. In one bizarre interlude, Swede is taunted, duped and nearly seduced by a radical leftist named Rita (Valorie Curry), who claims to be a conduit to Merry. The Rita character is such an overwrought hippie-dippie stereotype, it’s as if she wandered into the movie from a community college production of “Hair.’ (No offense, community college productions of “Hair.”)

“American Pastoral” opens with the 45-year-high school reunion of Roth’s famed alter ego Nathan Zuckerman (David Strathairn), who was friends and classmates with Swede’s younger brother Jerry (Rupert Evans).

Swede, says Jerry, is dead. That cues the extended flashback and off we go to a time when the Swede was young and full of life, and the rest of the story progresses from there.

But we can’t quite shake off the feeling we’re watching something that’s D.O.A.

1⁄2

Lionsgate presents a film directed by Ewan McGregor and written by John Romano, based on the novel by Philip Roth. Rated R (for some strong sexual material, language and brief violent images). Running time: 108 minutes. Opens Friday at local theaters.