Elvis had a twin brother who was stillborn. “The Identical” explores a “What if he survived?” story line, rich with possibilities, and squanders it on a mess of a movie bogged down by earnest intentions.

It opens on a dusty road between cotton fields outside Decatur, Ala., in 1972, where a zombified rock star tricked out more like Slash from Guns N’ Roses than Elvis gazes out the car window as a signal that flashbacks are about to commence.

Cut to old-timey piano music and black-and-white depiction of a Depression-era couple too poor to support both of their newborn sons. They give one up to be adopted by an evangelical preacher (a cringingly miscast Ray Liotta), and his wife, Ashley Judd, given little to do but smile vacantly.

The adopted boy, Ryan, grows up adored but expected to follow in Daddy’s footsteps, while the poor one, Drexel, becomes an early star of rock ‘n’ roll (both are played by real-life Elvis impersonator Blake Rayne, who does bear a striking resemblance to the King, especially the Greek nose). Unaware of their connected DNA, the preacher’s kid watches his uncanny look-alike get more and more famous, itching to fulfill his own musical ambitions as he works as a mechanic. When he enters a Drexel impersonator contest that seems too much like “American Idol” for its era, his pop-idol bro, also in the dark about the twin situation, turns up to finger him as the winner.

Sounds like a great setup for a Cain and Abel-style rivalry (fitting enough for the film’s religious overtones), but “The Identical” is laced throughout with so much cornpone sincerity and moronic dialogue, it’s neither fun nor moving. Every cliché is milked, every opportunity to oversimplify snatched and pounded into the Dixie dirt.

The film, directed by Dustin Marcellino, includes a few other known stars — Joe “Hey, it’s a gig” Pantoliano as Ryan’s boss at the garage, Seth Green as a drummer and Minnesota’s own Chris Mulkey, a fine character actor who here turns in the most mawkish performance of his career as the twins’ natural father later in life.

The music of both brothers is bland, affectless and almost pointedly unlike Elvis’, as if Graceland lawyers dictated which chord progressions were off limits. The staggeringly banal lyrics make even Elvis’ seem intellectual.

“The Identical” has grand ambitions, but they fall flat amid a muddled message and a strong whiff of righteousness.