Ben Platt and Micaela Diamond star in a timely and gorgeously sung Broadway revival of the 1998 musical about the Leo Frank case.You do not expect the star of a musical about a man lynched by an antisemitic mob to be his wife. Especially when that man, Leo Frank, who was murdered in Georgia in 1915, is played, with his usual intensity and vocal drama, by Ben Platt.Yet in the riveting Broadway revival of the musical “Parade” that opened on Thursday at the Bernard B. Jacobs Theater, it’s Micaela Diamond, as Lucille Frank, you watch most closely and who breaks your heart. With no affectation whatsoever, and a voice directly wired to her emotions, she makes Lucille our way into a story we might rather turn away from.True, this alters the balance of the show as originally staged by Harold Prince in 1998, further tipping it toward the marriage instead of the miscarriage of justice. Also toward the rapturous score by Jason Robert Brown, which won a Tony Award in 1999. But since the legal procedural was never the best part or even the point of “Parade,” the enhanced emphasis on a love story tested by tragedy and set to song is a big net gain.It’s strange, of course, to talk about net gains in relation to such a horrible tale. But “Parade” has always been strange anyway, seeking to make commercial entertainment out of a violent history and, because he’s a victim, a hero of a nebbish.As Alfred Uhry’s book — also a Tony winner — relates, Leo, the manager of a pencil factory owned by Lucille’s uncle, is a misfit in Atlanta: a New York Jew but also a cold fish. In Platt’s highly physical interpretation, he is scrunched and sickly looking, as if literally oppressed by the gentile society around him. That Lucille’s family, longtime Southerners, seems warmly assimilated into that society makes their marriage, at the start, a curdling of cream and vinegar.Michael Arden’s staging, imported with a slightly different cast from the City Center gala he directed in November, rightly relishes such contrasts. He signals the primacy of the love story by starting, in the 1860s, with sex: a young Confederate soldier bidding goodbye to his girl. A foreboding Dixie anthem called “The Old Red Hills of Home” leaps 50 years forward to connect the white Christian bigotry that fueled the Civil War to the war against Leo as well.His troubles begin with the murder of Mary Phagan (Erin Rose Doyle), a 13-year-old white employee who works, for 10 cents an hour, fastening erasers to pencil caps. Lacking conclusive evidence and in dire need of a conviction, the district attorney, Hugh Dorsey (Paul Alexander Nolan), railroads Leo by suborning testimony from many sources: friends of Phagan, a cleaner at the factory (Alex Joseph Grayson) and even Minnie, the Franks’s maid (Danielle Lee Greaves). After a sensational trial that cynically pits Jewish Atlantans against Black ones, Leo is sentenced to hang.The minimal set by Dane Laffrey is essentially a high platform on a low one, suggesting a witness box, a cell and a scaffold, our critic writes.Sara Krulwich/The New York TimesWhen the first act ends on that awful note, we still do not know Leo well. His first song, usually in musicals a moment for ingratiation, is instead a bitter snit called “How Can I Call This Home?” His last before the verdict is “It’s Hard to Speak My Heart.” Whatever that heart really holds is further blurred by Uhry’s device of having Leo enact the false testimony of other characters, so we see him as a rake and a maniac before we’ve grasped him as a man.Arden begins to correct for that during the intermission, which Leo, now imprisoned, spends sitting onstage with his head in his hands. In Act II, as he recognizes his growing dependence on Lucille, she finally becomes real to him and thus he to us.It’s too bad that some of this enlightenment is achieved through huge elisions and license in relating what is still a contested history. Though it’s true that Georgia’s governor (Sean Allan Krill) opened an inquiry that led to the commutation of Leo’s death sentence — but only to life in prison — it’s doubtful he did so as a result of Lucille’s buttonholing him at a tea dance. Nor that she accompanied him like a lay detective as he reinterviewed witnesses and obtained their recantations.Even if true, it’s unconvincing here, presented almost as a series of Nancy Drew skits. Still, Diamond maintains her dignity, allowing the final phase of the tragedy — in which Leo, after two years of appeals that are summarized in one line, is kidnapped from his cell and hanged — to commence with the drama righted.It is never wronged as long as Brown’s music plays. In this, his first Broadway show, he demonstrates the astonishing knack for dirty pastiche that has informed such follow-ups as “The Last Five Years,” “13” and “The Bridges of Madison County.” “Pastiche” because of his inerrant ear for just the right genre to fit any situation, in this case including Sousa-style marches, work songs, blues, swing ditties for the factory girls, a dainty waltz for the governor’s party. “Dirty” because he roughs them up with post-Sondheim technique, scraping the surface to bring up the blood.Douglas Lyons and Courtnee Carter sing the mordant “A Rumblin’ and A Rollin’” as hysteria about the case grows.Sara Krulwich/The New York TimesAnd as one of the few musical theater composers to write his own lyrics successfully, he gives singing actors something to act. He also manages to achieve in a rhyme what would otherwise take a scene of dialogue. As the politicians and journalists foment local hysteria and national media interest in the case, he gives two Black workers in the governor’s mansion a mordant triplet in the song “A Rumblin’ and a Rollin’”: “I can tell you this as a matter of fact/that the local hotels wouldn’t be so packed/if a little Black girl had been attacked.”That the Black workers (Douglas Lyons and Courtnee Carter) are otherwise barely characterized is one of the more obvious signs that the show’s book was written in the 20th century. (Uhry has made some revisions for this production.) Arden addresses this by keeping the ensemble as particular as possible, never letting it devolve into vague masses making generic gestures. And in minimizing the visual elements — the set (by Dane Laffrey) is essentially a high platform on a low one, suggesting a witness box, a cell and a scaffold — he keeps our attention on the people and what they sing.If actual history plays second fiddle to that — by the way, there’s a terrific orchestra of 17 players, just two shy of the plush original — current history steps in as a pretty good substitute. Not just in the guise of revitalized antisemitism, though the show’s first preview, on Feb. 21, was greeted by a small gaggle of neo-Nazi demonstrators.What struck me even more vividly in this well-judged and timely revival is the quick path hysteria has always burned through the American spirit if fanned by media, politicians and prejudice of any kind. When a chorus of white Georgians chants “hang ’im, hang ’im, make him pay,” the words can’t help but echo uncomfortably in the post-Jan. 6 air. And another song, a prayer for a return of the day when “the Southland was free,” sounds a lot like current talk of a second secession.Our historical wounds never really heal over. Though Frank’s death sentence was commuted, he was killed anyway and, as “Parade” points out, never exonerated. That case is ongoing.ParadeThrough Aug. 6 at the Jacobs Theater, Manhattan; paradebroadway.com. Running time: 2 hours 30 minutes. More