Washington - At the Cannes film festival last month, the scandal arrived with metronomic predictability: Quentin Tarantino's "Once Upon a Time in ... Hollywood" might have been the week's hottest ticket and Korean filmmaker Bong Joon-ho might have taken the cherished Palme d'Or.
But it was Abdellatif Kechiche's "Mektoub, My Love: Intermezzo" that set tongues wagging, literally and figuratively.
The nearly four-hour film caused a ruckus, not just because of its derriere-numbing running time (most of it spent observing nubile teenage girls twerking to a pounding soundtrack of club music), but because of a 15-minute scene of cunnilingus, filmed so realistically that questions immediately arose as to whether it was unsimulated.
Graphic sex is a longtime staple at Cannes, where in 2003 director Vincent Gallo outraged audiences with a scene of him receiving oral sex from Chloë Sevigny in "The Brown Bunny," and where 10 years later viewers were confronted with the sight of several male members in various degrees of tumescence in "Stranger by the Lake," followed by a 17-minute sex scene in Kechiche's lesbian coming-of-age story "Blue Is the Warmest Color."
The actresses in "Blue Is the Warmest Color" intimated that they felt poorly treated by Kechiche on the set of that film. This year, he faced accusations that he plied his young "Intermezzo" actors with alcohol until they engaged in real-life sex acts for the camera.
Meanwhile, as that controversy played out on the Riviera, US audiences were flocking to see "John Wick 3," in between making "Avengers: Endgame" and "Aladdin" huge hits. One of them a dark, fetishistically violent thriller, one a live-action comic book, one a Disney fairy tale, all resolutely sex-free.
Thus does a familiar pattern repeat itself: The summer begins with a new crop of sexually explicit, mostly European movies set off from Cannes to the festival circuit and eventually to brief art-house runs, while Hollywood churns out its chief export of gun-happy escapism and wholesome kid stuff.
Between those two channels the classic sex scene - once a staple of high-gloss, adult-oriented, mainstream movies - has been largely forgotten and ignored, recommitted to very esoteric margins it sprang from generations ago.
Sex has always been a part of American cinema: Ninety years ago, Louise Brooks scandalized audiences with her brazen, exhilaratingly unabashed eroticism in the silent classic "Pandora's Box." In the late 1920s and early 1930s, before the enforcement of the censorious Hays Code, film studios competed over whose movies could be the most daring, and delighted in sneaking naughty material past local decency boards.
Although the Golden Age of Hollywood - during which the industry censored itself by way of the Production Code - produced some deliciously provocative innuendo and ingenious workarounds, it wasn't until the 1950s and 1960s, when American audiences were able to see new, explicit films from postwar Europe, that sex became not just titillating but downright respectable: Such films as "And God Created Woman" and "Belle de Jour" introduced a new formal convention to discerning cineastes who could couch their more prurient instincts in terms of liberated expression, highbrow sensuality and uncompromising realism.
Of course, even the artiest imports were canny enough to have it both ways: 1972's "The Last Tango in Paris" was just one example of what could be gained from cultural importance conferred by critics while enjoying the free publicity garnered by its most scandalous content - in this case, a scene of Marlon Brando sodomizing co-star Maria Schneider with a stick of butter.
But those films proved germinal for a generation of filmmakers whose cinematic ideals were shaped during that era, and who then took its most outré sensibilities to Hollywood, where they softened their most transgressive edges.
The 1980s and early 1990s were a heyday of sex scenes that might have been hot and heavy but stayed within the parameters of bourgeois good taste: Movies such as "An Officer and a Gentleman," "Body Heat," "9½ Weeks," "Fatal Attraction" and "Basic Instinct" were must-see films, not just because of their twisty plots but because of sex scenes that were frank, artfully staged and, sometimes, arousing in their own right.
Arguably, seduction and suggestion are almost always sexier in movies than the act itself - witness Cary Grant and Ingrid Bergman's prolonged kiss in "Notorious" or Kevin Costner painting Susan Sarandon's toenails in "Bull Durham."
But when a sex scene works - when it exists for more authentic reasons than shock value or sophomoric giggles and manages to involve viewers more deeply than mere voyeurism - it exemplifies one of those rare things that movies do best.
Well-conceived sex scenes are capable of producing a spontaneous physical frisson just as cathartic - and gratifying - as a sudden belly-laugh or a good cry. As the critic Jonathan Rosenbaum has noted, movie sex "is the ultimate special effect."