As if to prove there is balance in the universe, perhaps the finest of all screen adaptations of a novel by Philip Roth—James Schamus’ “Indignation”—is quickly followed by one of the weakest. Perhaps Ewan McGregor genuinely admires Roth’s 1997 book “American Pastoral,” but one could never tell that from the effortful, plodding film, which the actor not only stars in but directed as well.

The problems start with the script by John Romano, a long-time writer-producer (mostly for television) who’s occasionally penned screenplays in the past. But they’ve been based on novels that weren’t in Roth’s class—“The Lincoln Lawyer,” “Nights in Rodanthe,” “The Third Miracle.” And while he follows Schamus’ method of drawing dialogue from the page, thereby retaining the author’s voice, his work is hobbled by several factors. This is a much heftier book than “Indignation,” and the trimming accentuates the archness and artificiality of the speech. Moreover, the delivery isn’t handled with a similar degree of deftness as it was in “Indignation”—a flaw that has to be ascribed to the film’s first-time director.

Simply put, McGregor’s helming is flatfooted throughout. Unlike Schamus, he seems to have been so obsessed with getting the period visuals correct—and in truth production designer Daniel B. Clancy and costume designer Lindsay Ann McKay have done a splendid job in that respect—that he’s forgotten to instill any dramatic urgency into the scenes, which come across more as stilted rehearsals rather than finished products. Of all the performances, only one stands out—that of Peter Riegert as the protagonist’s outspoken father. It’s basically just a vaudeville turn, but it possesses a coarse vitality and directness that’s positively refreshing compared to what’s going on around him.

That observation applies particularly to McGregor’s leading turn. To begin with, while the actor succeeds in managing a fairly good American accent, he’s physically unconvincing as Seymour “The Swede” Levov, the blonde, brawny Jewish New Jersey boy who’d had a stellar high school athletic career. Had he been able to bring some authentic human feeling to the character, McGregor might have overcome that, but as it is, Swede emerges in his hands as a sort of mannequin whose stiff movements and stilted vocal inflections belie the notion that the guy is supposed to be incredibly charismatic.

But under McGregor’s heavy directorial hand, the rest of the cast fare poorly as well. Jennifer Connelly is cast as Dawn, the Catholic beauty whom Swede weds. She’s a fine actress, but finds no key to the character, which—apart from her interest in cattle and a later obsession with plastic surgery (the reason behind which, explained in the novel, is fudged here)—seems curiously bland. Swede and Dawn have a daughter together named Merry, who has a pronounced stutter. She’s initially played—and very well—by Hannah Nordberg. But when the story moves into its later years and the role is taken over by Dakota Fanning as a surly teen furious over the Vietnam War and radicalized by friends in the city, the character turns into a shrill, one-note caricature. And she is the centerpiece of the story’s major arc, in which an explosion at the small local post office, which kills the postmaster, is accompanied by her disappearance and presumed guilt. It’s Swede’s determination to track her down—and protect her even if she committed the crime—over the years, and their eventual reunion, facilitated by a radical intermediary named Rita (played by Valorie Curry as a grinning would-be seductress)—that forms the center of the narrative. It should be powerful stuff, but comes across instead as a pallid Lifetime Network clone.

As if that weren’t bad enough, Romano and McGregor have opted to retain the book’s framing device—a meeting at a high school reunion between Roth’s surrogate Nathan Zuckerman (David Strathairn) and Swede’s brother Jerry (Rupert Evans), who informs the surprised Zuckerman of Swede’s unhappy life. Evans has the misfortune of having to deal with some of the worst old-age makeup seen in many a year (though it’s rivaled by that donned by McGregor in a montage toward the close), but that doesn’t explain the woodenness of the interplay between him and Strathairn, a fine actor reduced to a clumsy use of tics that would be rejected as inauthentic in a beginning drama class.

Apart from a sadly undistinguished effort by composer Alexandre Desplat, who ordinarily produces inventive scores even for less than stellar films, “American Pastoral” boasts fine craft contributions. It certainly looks beautiful, with Martin Ruhe’s lustrous widescreen images luxuriating in the work of Lindsay and McKay. But while fastidiously made, McGregor’s film is dramatically inert—a pretty but shallow rendering of Roth’s novel.