Steven Levenson has written a big old-fashioned family drama in “If I Forget,” and the notable thing about the production at Studio Theatre is that it’s acted to the hilt. Levenson writes long scenes right out of the Henrik Ibsen playbook, loaded with exposition, debate and revelation, and the cast settles into the script’s household realism for a nearly three-hour tour.

Despite the stem-winding performances of director Matt Torney’s smart-talking ensemble — all of them deft at delivering jabs that hurt inside the Jewish family but that make the audience laugh — the plot doesn’t warrant that heft. “If I Forget” is a good drama but not a mighty one, despite the way the Bethesda-raised Levenson (who wrote the book for the musical “Dear Evan Hansen”) links D.C. gentrification in 2000 to the gloomy new reality of Israel and the Palestinian territories as peace talks break down. The synchronicity of these two distant worlds is not always crystalline, though there is plenty of knotted history and arguments about tradition and expediency to keep you wondering where Levenson is finally going to land.

“It’s all just dirt,” declares Michael, an academic who refuses to get sentimental over territory anywhere, whether it’s Jerusalem or Washington.

Michael, played with epic eruptions of righteous passion by Jonathan Goldstein, is a scholar about to publish one of those controversial, scandalize-the-family books (one that too obviously might sink his pending tenure chances, but let that pass). Lou Fischer, Michael’s dad, is a World War II veteran who’s not about to loosen his grip on the memory of the Holocaust, and Richard Fancy plays Lou’s pivotal scene in a voice that sounds roughed up by history.

The plot has lots more threads, but Levenson eventually boils it down to money — which gets tight due to unforeseen events that are pure early Internet — and property. Lou lives in Tenleytown and owns a shop on 14th Street NW; none of the Fischer siblings can agree on what to do with the shop. The anti-gentrification Sharon (an earthy Robin Abramson) wants to keep it, arguing on behalf of the Guatemalan family that runs a grocery store there. The upscale Holly (rendered tartly by Susan Rome) wants to occupy it with her start-up interior-design business. Michael needs the money and wants to sell.

There are more generations — a slouchy teen (Joshua Otten, in the only awkwardly written role) and an unseen daughter away in Israel for the first act — plus an oxygen tank and a wheelchair in the upstairs bedroom of Debra Booth’s functional two-story set, artifacts of aging and death. The siblings’ mother recently died, and in the second act, as George W. Bush takes office and the trio snipe over their votes, Lou is ailing. You feel the passing of the guard and the haggling over how to inherit old issues and somehow forge ahead.

There is nothing showy about the staging and nothing slick for the characters to do except talk everything out in the bedroom upstairs or the dining room below. The anxiety drips off Paul Morella as Holly’s seemingly rich lawyer husband, and Julie-Ann Elliott plays Michael’s wife diplomatically, part of the clan but slightly outside.

“If I Forget” opened the same weekend as “The Pianist of Willesden Lane,” Mona Golabek’s moving solo performance about her mother’s escape from Nazis as a child (presented by Theater J at the Kennedy Center’s Family Theater). The philosophical contrast between the shows is sharp: Golabek sanctifies her history. Levenson is not sure exactly how Jewish identity will survive or what the 21st century will bring. It’s that uncertainty, lucidly articulated by characters whose competing arguments almost balance out, that so humanely destabilizes this household.

If I Forget, by Steven Levenson. Directed by Matt Torney. Costumes, Helen Huang; lights, Michael Giannitti; sound designer and composer, Nick Kourtides. About two hours and 50 minutes. Through Oct. 14 at Studio Theatre, 1501 14th St. NW. $60-$104. 202-332-3300 or studiotheatre.org.

Correction: A previous version of this article misspelled Mona Golabek’s name.