In the decades since Julius and Ethel Rosenberg were convicted of conspiracy to commit espionage and executed in New York in 1953, the Jewish couple have become larger-than-life icons.

To those on the left, the Rosenbergs are the archetypal victims of the anti-communist fervor of the ’50s. They were railroaded by the FBI and the judicial system with the full backing of a ruthless government, or so their defenders claim.

Conservatives, on the other hand, see them as traitors who funneled sophisticated technical secrets to the USSR in the crucial postwar period, and got what they deserved.

Meanwhile, literary works such as novelist E.L. Doctorow’s “The Book of Daniel” and playwright Tony Kushner’s “Angels in America” simultaneously drew inspiration from the Rosenberg saga and burnished its legacy.

Inevitably, their elevation to symbols precludes the Rosenbergs from being seen as ordinary people. And that’s the side of Ethel and Julius that their thirtysomething granddaughter, Ivy Meeropol, wants to explore.

In her worthwhile though uneven documentary, “Heir to an Execution,” Meeropol sets out on a personal journey to know and understand her antecedents as human beings rather than as mythic representations.

Meeropol, of course, recognizes that the average viewer is more interested in the weightier aspects of the Rosenberg case than in family scrapbooks. So she uses a slew of archival footage in a mostly deft, occasionally awkward attempt to weave together the private and historical.

“Heir to an Execution: A Granddaughter’s Story,” which debuted in competition at the Sundance Film Festival in January, premieres Monday, June 14, on HBO. It also screens next month in the San Francisco Jewish Film Festival with Meeropol on hand.

The film doesn’t provide a detailed analysis of either the early ’50s or the Rosenbergs’ trial, presuming a certain knowledge on the viewer’s part. We glean that numerous idealistic college students viewed communism as a kind of utopian system, and that plenty of young middle-class Jews paid more than lip service to opposing the injustice they saw in postwar America.

Meeropol tracks down Morton Sobell, who was tried with the Rosenbergs, and their contemporary Miriam Moskowitz, both of whom were essentially convicted for refusing to name names.

The best interviewee is Meeropol’s father, Michael, long an eloquent and thoughtful speaker about his parents. He’s clearly at peace with Julius and Ethel and what they did or didn’t do, and he observes Meeropol’s pursuit with pride and bemusement.

Alas, Meeropol’s forays into family history provide a series of uncomfortable home-movie moments. As she drives past the house where David Greenglass lives — he’s the tragic, conflicted figure who put the Feds on to his sister Ethel and brother-in-law Julius (and served a 10-year sentence himself) — Ivy tears up, horrified by the innocuous homogeneity of his bungalow.

Meeropol contacts relatives who distanced themselves from the Rosenbergs amid the national hysteria, and who made no attempt to adopt Michael or his brother, Robert, after the executions. They’re not pleased to hear from her half a century later, although she finally finds a second cousin her own age who agrees to meet on camera. (He’s a mensch who offers an apology, but the scene has a “What’s the point?” quality.)

One gets a similar feeling when Meeropol takes her dad and uncle to the New York apartment where they lived in the early ’50s, and where Julius was arrested before their eyes. They stand in the kitchen, echoing a famous photo of Ethel at the sink, but the moment doesn’t resonate with us the way it clearly does with the Meeropols.

Ivy Meeropol gets points for bravery and persistence, not least when she confronts her father about the classified government documents released in 1995 that seemed to confirm that Julius was indeed passing information to the Soviets, but that Ethel was innocent.

The implication is that the government tried and convicted Ethel of a capital crime in order to pressure her — and Julius — into confessing and naming others. We’re left with the image of a loving, committed couple who shared political principles and would not turn on each other or their acquaintances — even if it meant their children suffered.

“Heir to an Execution” is both a contribution to the historical record and an admirable effort to breathe fresh life into a 50-year-old story. As a family story, though, it doesn’t have the emotional impact it so clearly intends.

“Heir to an Execution: A Granddaughter’s Story” premieres 11 p.m., Monday, June 14, on HBO, and airs several other times during the month.