(Stan Barouh/Guy Kapulnik and Paul Morella in “After the War.”)

Motti Lerner’s new play, “After the War,” explores the depths of alienation in an Israeli family irrevocably divided by the country’s near-perpetual state of war. But if the vague and unsettled feeling it leaves you with is intentional, the sense that the piece needs to go deeper is not.

The family is that of Joel (Paul Morella), a concert pianist who has returned to Israel for the first time in 18 years to visit his sullen mother (Barbara Rappaport), see his resentful soldier-son (Guy Kapulnik) and, most significantly, perform as a guest artist with the Israel Philharmonic Orchestra. Owing to his long-standing public opposition to Israel’s policies toward the Arabs, Joel is not exactly welcomed home joyfully. It is, in fact, the family’s blistering belligerence toward Joel that drives the work — a bitter underscoring that is a counterpoint to the beauty of the classical music Joel plays.

The playwright paints his drama, being given its world premiere by Mosaic Theater Company at the Atlas Performing Arts Center, in murky hues, the kind that are meant to keep us guessing at who these people are and what they think. Can Joel, for example, be so thick about the turmoil his presence will cause? For what reasons does Trudy (Tonya Beckman), the nurse who cares for Rappaport’s Bella, tolerate the advances of all of the men of the play? Why is Joel’s son Izzy, studying in Jerusalem after his service in Israel’s 2006 war with Hezbollah in Lebanon, so secretive about the serious, untreated injuries he shows up with at Bella’s flat? The problem is not so much that not every question gets an answer, but that an audience is unable to parse the little mysteries in ways that help them make sense of what’s really going on.

The confoundingly impassive surface of “After the War” is summed up in the hostile silences into which Bella lapses at regular intervals, as Joel seeks to draw her out. Putting up a stony front may be true to life, but being rendered speechless doesn’t in this instance allow for much dramatic oomph.

“After the War” is the seventh collaboration between Lerner and Mosaic’s artistic director, Ari Roth, going back to Roth’s long tenure at Theater J, which he left late in 2014. Its focus on an artist at political odds with his government contains obvious parallels to Lerner himself; a dramatist who has repeatedly and admirably touched the rawest nerves in Israeli society, on such conscience-driven issues as the West Bank settlements and the behavior of Israeli soldiers in war, Lerner has often had more success getting plays staged outside his homeland than in. (This is a play that is being produced in English translation before it ever is mounted in the original Hebrew.)

Sinai Peter, who directed Lerner’s “Pangs of the Messiah” and “The Admission” for Theater J, here has the challenge of using a big, wide Atlas stage that feels as if it’s a mismatch for such an intimate play. Set designer Frida Shoham is required to cover a lot of turf with a few sticks of furniture and behind it, oddly, the empty chairs and music stands of an orchestra. The most meaningful element of the set is the battered grand piano that sits prominently in the apartment of Bella, a renowned music teacher, and on which Joel practices the piece he is to play with the philharmonic, Beethoven’s “Pathétique” Sonata.

The idea of Joel’s emotional isolation is one of the more fully realized aspects of “After the War”; this is a play about a man who has in both real and metaphoric dimensions lost his family and his country. As Morella sits at the piano, consumed in Joel’s artful task, the music manages to do what words are no longer capable of: filling the awkward gaps between the characters. These people lack the ability to speak patiently and meaningfully to one another, and not only about Israel’s endless war. It’s as if the nation’s traumas have so addled the brains of its citizens that normal patterns of communication have corroded, even among people who’ve known each other all their lives.

The performances reflect this impression of dislocation; the actors, while well-cast, seem to drift a bit uncertainly through the story. Interestingly, Michael Tolaydo, as the production’s most elusive character, Bernard — Trudy’s irritating mooch of an ex-husband — offers up the most grounded (and amusing) portrayal. As with virtually everyone else, you could wish that Morella was given a sturdier foundation on which to construct a more compelling version, in his case of a headstrong artist who has sacrificed so much on the altar of his principles.

After the War by Motti Lerner. Directed by Sinai Peter. Translation, Roy Isacowitz; set and costumes, Frida Shoham; lighting, Michael Lincoln; music and sound, Eric Shimelonis; dialect, Cristina Bejan. With James Whalen. About 1 hour 45 minutes. Tickets, $15-$60. Through April 17 at Atlas Performing Arts Center, 1333 H St. NE. Visit mosaictheater.org or call 202-399-7993 Ext. 2.