Pablo Picasso’s most readily accessible painting isn’t in a museum. It hangs in a New York restaurant, in a building whose owner reportedly thinks that the painting is a piece of junk and wants to get rid of it.

Picasso’s Unmovable Feast

TERRY TEACHOUT

Feb. 13, 2014 3:39 p.m. ET

Pablo Picasso’s most readily accessible painting isn’t in a museum. It hangs in a New York restaurant—a restaurant that is housed in a building whose owner reportedly thinks that the painting is a piece of junk and wants to get rid of it.

“Le Tricorne” is a 19-foot-tall canvas that Picasso painted in 1919 for Sergei Diaghilev’s Ballets Russes. It was originally used as a curtain for “The Three-Cornered Hat,” a now-classic ballet composed by Manuel de Falla and choreographed by Léonide Massine for which Picasso designed the sets and costumes. John Richardson, Picasso’s biographer, considers the décor for the ballet to be his “supreme theatrical achievement,” and the curtain is a priceless relic, one of the last surviving souvenirs of the most influential ballet company of the 20th century. Forty years after Picasso painted it, Philip Johnson incorporated “Le Tricorne” into his plans for the Four Seasons Restaurant, which is located in Mies van der Rohe’s Seagram Building, a 38-story skyscraper that is itself a classic of modern architecture. Ever since the Four Seasons opened in 1959, “Le Tricorne” has hung in the entryway, where it can be seen not only by patrons but by passers-by. The interior of the Four Seasons was designated as a landmark in 1989, meaning that it can’t be altered without official approval.

End of story…right? Not even close.

Because “Le Tricorne” is a painting, it’s not a physical part of the Seagram Building. So even though it’s now owned by the New York City Landmarks Conservancy, it’s not covered by the landmark designation—and Aby Rosen, a real-estate developer whose company, RFR Holding, owns the building, wants to move it. RFR is claiming that the wall on which “Le Tricorne” was hung by Johnson is in imminent danger of collapse and needs to be rebuilt. The Museum of Modern Art has offered to store “Le Tricorne” but not to display it, and art conservators believe that the painting, which is brittle, can’t be moved without destroying it.

According to the New York Times, Mr. Rosen, an art collector who goes in for avant-garde work, doesn’t like “Le Tricorne” and would prefer to hang pieces from his own collection in the space that it currently occupies. One person actually claims to have heard him dismiss the painting as a “schmatte,” which is Yiddish for “rag.” And since Mr. Rosen owns the Seagram Building, he’s legally entitled to demand that the Landmarks Conservancy remove “Le Tricorne,” even if it fails to survive.

Justice Matthew F. Cooper of the New York State Supreme Court issued a temporary injunction last Friday preventing RFR Holding from moving the painting, which had been scheduled to be taken down two days later, until the case can be heard on March 11. “I don’t want to be the judge who has a Picasso destroyed,” he said. And Belmont Freeman, an architect who worked on a 2008 restoration of the Four Seasons, published a piece in Architectural Record claiming that RFR Holding wasn’t telling the truth when it said that the wall could collapse. “The terrible prospect of a slab of travertine [marble] delaminating from the wall and ripping through the curtain, as RFR claims, is utterly specious,” he wrote.

The power to declare a building an architectural landmark is not to be wielded lightly. Constant change is necessary if a city is to remain culturally vital. But some buildings are indisputably important enough to deserve that status, and if there’s any building in New York that fills the bill with room to spare, it’s the Seagram Building. Likewise the Four Seasons, which is as significant a landmark in the history of midcentury modernism in New York as Frank Lloyd Wright’s Guggenheim Museum. It deserves to be preserved—and even though a technicality prevented “Le Tricorne” from being covered by its landmark status, everyone who’s seen the painting knows perfectly well that it, too, is an essential part of the design of the Four Seasons Restaurant. It’s one of the cultural glories of Manhattan.

Legend has it that the 19th-century robber baron Cornelius Vanderbilt, when told that something he wanted to do was illegal, responded by asking, “Law? What do I care about law? Hain’t I got the power?” It may well be that Mr. Rosen is legally empowered to take down “Le Tricorne,” and in so doing run the very real risk of destroying it. We’ll find out a few weeks from now. But it shouldn’t have to come to that. Mr. Rosen claims to appreciate art. Well, here’s the acid test of his appreciation: Is it really so important for him to hang his Damien Hirst and Jeff Koons pieces in a space that was custom-tailored by Philip Johnson to show off a treasure of modernism like “Le Tricorne”? Now’s his chance to show that he truly cares about great art—or, conversely, to prove that he doesn’t know the difference between an investment opportunity and an immortal masterpiece.