Whenever opera turns to Broadway, many opera fans clutch their pearls in tut-tutting horror. That’s a lot of pearl clutching, because more opera companies are doing it, from the Glimmerglass Festival to the Chicago Lyric Opera (which offers its annual musical outside the parameters of the regular season, to smooth the ruffled feathers of subscribers) to the Washington National Opera, which offered “Show Boat” a couple of seasons back.

Then there are the singers who venture onto Broadway — most recently Renée Fleming, who may or may not have retired from opera with her recent “Der Rosenkavalier” at the Metropolitan Opera, but who has announced that she will appear next year in a new production of “Carousel.” Cue another round of disapproval.

An interviewer recently asked what I thought of a singer taking the highest of art forms and making it popular. He was referring to Luciano Pavarotti, but the basic premise is indicative of what bothers opera lovers about Broadway — as well as demonstrating a profoundly flawed set of assumptions about “high” and “popular” art. Opera, like cinema, has always had a long tradition of multiplex-level, popular hits offsetting its more highbrow, arthouse-like products. As for Broadway: Opera and Broadway have had a long and fruitful relationship. It’s just some opera fans who need catching up.

Broadway and opera have a long history together. Broadway has been a home for a number of operas: the Gershwins’ “Porgy and Bess” (1935); Thomson and Stein’s “Four Saints in Three Acts” (1933); Menotti’s “The Medium” and “The Telephone” (1947), “The Consul” (1950) and “The Saint of Bleecker Street” (1954); Blitzstein’s 1949 “Regina” (itself based on a Broadway play, Lillian Hellman’s “The Little Foxes”); or Bernstein’s “Candide” (1956, with sundry revisions and revivals). Broadway has also offered a home to some opera singers: most famously Ezio Pinza, who got an unexpectedly triumphant last act to an illustrious opera career when he and Mary Martin starred in Rodgers and Hammerstein’s “South Pacific” (1949). Lawrence Tibbett, in his day a heartthrob American baritone, acted in several films in the 1930s and turned to Broadway in the 1950s, after his opera career had started to wind down. Then there were mid-career singers who effectively became Broadway artists, such as Christine Johnson, who originated the role in “Carousel” (1945), Nettie Fowler, that Fleming will take in the new revival.

[The opera-izing of the American musical.]

Opera star Paulo Szot and Broadway leading lady Kelli O’Hara in the 2008 Lincoln Center Theater revival of Rodgers and Hammerstein’s “South Pacific.” (Joan Marcus/ Philip Rinaldi Publicity via AP)

Broadway has also served as an incubator for operatic talent. Baz Luhrmann’s 2002 Broadway staging of “La bohème” — which introduced Puccini’s opera to many theatergoers and sent the opera crowd into paroxysms because of its use of amplification — featured three casts of classically trained singers; some, such as the bass-baritone Daniel Okulitch and the tenor Jesus Garcia, went on to active opera careers. The 2008 revival of “South Pacific” on Broadway gave the baritone Paulo Szot, who reimagined the role of Emile de Becque in a younger and handsomer vein, an entree to a significant international opera career. And it didn’t hurt David Pittsinger, either, although the bass-baritone was already well established when he joined the production as Emile later in the run.

“Lower?” “Higher?” Say, rather, simply different. It seems arbitrary to assert that Broadway musicals exist in a separate category from an art form that happily embraces popular forms such as opera comique, singspiel and operetta (all of which involve spoken dialogue interspersed with sung numbers). Those opera lovers who profess to look down on musicals act as though the genre were best represented by “Aaron Slick from Punkin Crick,” a 1952 hillbilly film best remembered for occasioning a near-rupture between the opera star Robert Merrill and the Metropolitan Opera’s general manager Rudolf Bing. Bing ordered Merrill not to make the movie, and almost wouldn’t take him back when Merrill returned, hat in hand, begging for a second chance after the film flopped. Of course, not all musicals are this lousy — although to watch Deborah Voigt simper and coquette her way through “Annie Get Your Gun” at the Glimmerglass Festival a few years ago, you could be excused for forgetting that.

Now that the distinction between opera and Broadway has been reinforced by the amplification question — Broadway singers are heavily miked these days, and thus focus on different aspects of vocal production — it’s all too easy to forget that back in the pre-microphone days, Broadway singers could teach some opera singers a thing or two.

[Sure, they can sing (opera), but can they act?]

The musical “Carousel” is an object illustration. It’s widely acknowledged to be the most operatic of Rodgers and Hammerstein’s works: richly scored and vocally demanding. Yet the first few times I saw it onstage, even with operatic voices, I found it flat and dated, hampered by the hard-to-credit final act, in which the protagonist, Billy Bigelow, returns from the dead (a device that Verdi also used in “I Lombardi”). Not until I recently found videos of John Raitt, the original Billy, singing the piece did I finally understand. Raitt was a formidable technician with a big, easy voice; you can find video of him singing Figaro’s aria from “The Barber of Seville,” in English, but perfectly respectably. When he launches into “Carousel’s” famous “Soliloquy,” daydreaming about his unborn child, the piece loses the sense of artificiality, of a self-conscious Big Moment, that had always seemed to surround it whenever I’d seen it onstage. Most singers Perform it; Raitt simply delivered it as though it were a piece of acting that just happened to be sung, and topped with an effortless high B-flat at the end. Szot and Pittsinger have both said that “South Pacific” taught them about acting; Raitt bears out the idea that some opera singers have much to learn in this regard. And he was able to do it without a mic, eight times a week.

The most important distinction between opera and Broadway is one of approach. Every form of theater, musical and otherwise, has to be produced with a measure of what one might call stylistic tact. You don’t sing Mozart like grand opera — it sounds silly to belt out his graceful lines as though you wanted to reach the top balcony — and you don’t stage “The Merry Widow” as though it were “Aida” a passionate historical melodrama Yet some who have embraced the idea that Broadway is popular and has much to teach opera have taken it as a corollary that Broadway directors must be the best people to stage opera — as though this were an entirely new idea. Historically, some Broadway directors have become significant forces in opera: think John Dexter, think Frank Corsaro and others who were bitten by the opera bug. However, many who are hired today as though they represent the promise of opera’s future seem intimidated by the genre, such as Bartlett Sher, who has staged several uninspired Met productions (“Elisir d’Amore”) that contrast hugely with his successful work on the Broadway stage, including “South Pacific.”

I don’t see this as proof that opera, a “higher” art form, eludes them. Rather, I suspect that the mechanisms of a canonical art form — trying to break something free of many layers of tradition, in an institution, the opera house, not adept at rapid response — are more stultifying than the fast-paced atmosphere of a living one, a Broadway theater. It will be interesting to see whether Fleming can bring some kind of new life or spirit to Broadway — or whether, as seems more likely, and supported by historical precedent, it will be the other way round, and Broadway will bring new life to her.