The resemblance borders on uncanny. With the right haircut, the proper dose of blonde, Kristen Stewart IS Jean Seberg.

But the Iowa-born Seberg, made famous by “Saint Joan,” made immortal in “Breathless (“À bout de souffle”), had a spark that the always-underplaying Stewart never manages, even as she’s capturing the star-crossed starlet in the most traumatic period of her life.

And “Seberg,” a semi-historical account of Seberg’s radical 1960s political dilettantism and her pursuit and persecution by J. Edgar Hoover’s F.B.I., never quite jells into the tragic jeremiad and Oscar bait it was intended to be.

After Truffaut’s groundbreaking “Breathless,” Seberg pursued a career, half in Hollywood, half in France — married French novelist, filmmaker and diplomat Romain Gary (Yvan Atal) and had a son with him.

“Seberg” captures the star at 30, fretting over whether to take a lucrative, high-profile role in a Hollywood picture.

“It’s a Western…a Western musical. It’s irrelevant,” she complains to her agent (Stephen Root). “I want to make a difference.”

As the musical was “Paint Your Wagon,” a debacle like few others, she was right in the first regard. Flying Pan Am to Hollywood she impulsively dives into achieving the second. A Muslim militant, Hakim Jamal (Anthony Mackie) creates a “class” incident on her flight, and in an opportunistic instant, she throws in with his group for a photo op on the tarmac.

That gets the attention of the F.B.I., which is dedicated to undermining “elements in society who don’t like the way we do things here in America.”

Seberg is no dummy. She figures she was being baited on that flight, probably for money and public support. And she doesn’t know Jamal is an ex-con, an unstable womanizer who has done time in a mental hospital. That we learn from the F.B.I. agents assigned by their station chief (Colm Meany) to wiretap the movie star and track the movements of Jamal.

Jack O’Connell of “Unbroken” plays the agent with a conscience. Vince Vaughn plays the racist rageaholic inclined to top his boss’s “shine revolutionary” description of Jamal with a few choice uses of the N-word.

Mackie turns up the charisma, making Jamal a compelling speaker and master of rhetoric. When Seberg speaks of her “frivolous” work, he reassures her “The Revolution needs movie stars.”

They have an affair, and when the F.B.I. snoops stop making their “dark meat on the bone” cracks, they have what they need — a famous face giving “money and a platform” to radicals. Let the surveillance begin.

She feeds fuel to the fire. It’s 1968, Young Paris is on the streets, youth protests against racism, injustice and the Vietnam War are everywhere. And Seberg, living in France and returning to her native America, is good for a quote on that.

“This country is at war with itself.”

The surveillance scenes feel quaint — guys in white shirts and ties, sitting in a van or in HQ, listening to conversations and sexual encounters. Then you think of what they’re doing, a government agency spying on non-criminals, leaking embarrassing truths and in many cases, noxious lies to ruin “enemies of the state.”

Seberg gets wind of this and grows more paranoid by the hour after realizing that SOMEbody is deep into her business, destroying her marriage and her career.

Jamal, married to a leader in the Movement (Zazie Beetz), is feeling the heat, too.

Agent Jack starts to question the ethics of what he’s doing once his wife (Margaret Qualley) gets wind of it.

Stewart gets across Seberg’s spiking paranoia, but never lets us feel it. She’s a chill actress, and that keeps a barrier up that hurts the movie.

Watch her scenes with Mackie and Beetz. She practically wilts in their presence (especially the fearsome Beetz).

The script veers away from history with its whole “agent with a conscience” balderdash. The crazed partner Vaughn plays is straight out of bad melodrama.

And director Benedict Andrews underscores just how deeply he doesn’t “get it” by finishing the film with a long closeup of Stewart/Seberg, failing to wring emotions out of her, her failing to wring them out of us. Maybe that’s his way of throwing her under the bus, but a guy best known for stage works translated for the screen and “Una” didn’t do his star and her “star vehicle” any favors at any point.

MPAA Rating: R for language, sexual content/nudity and some drug use

Cast: Kristin Stewart, Jack O’Connell, Anthony Mackie, Margaret Qualley, Zazie Beetz, Yvan Atal, Stephen Root, Colm Meany and Vince Vaughn

Credits:Directed by Benedict Andrews, script by Joe Shrapnel, Anna Waterhouse An Amazon original release.

Running time: 1:42