A major Philip Guston retrospective that was set to open at the National Gallery of Art and three other museums starting next year has been postponed until 2024, in part because its images of the Ku Klux Klan and a lynching were deemed too sensitive for audiences and staff at this time.

Originally scheduled to open in June at the National Gallery of Art, “Philip Guston Now” was first pushed to next summer because of the museum’s pandemic-related shutdown. In a statement posted this week, the directors of the NGA, the Tate Modern in London, the Museum of Fine Arts, Boston, and the Museum of Fine Arts, Houston, announced that the exhibition would be delayed “until a time at which we think that the powerful message of social and racial justice that is at the center of Philip Guston’s work can be more clearly interpreted.”

“We recognize that the world we live in is very different from the one in which we first began to collaborate on this project five years ago,” the directors wrote. “The racial justice movement that started in the U.S. and radiated to countries around the world, in addition to challenges of a global health crisis, have led us to pause.”

Guston was a Canadian-born American who is widely considered one of the most influential artists of the past century. He died in 1980. “Philip Guston Now” would have been his first major retrospective in 15 years.

National Gallery of Art Director Kaywin Feldman said last week that the exhibition’s works depicting Ku Klux Klan hoods — more than two dozen such images in all — were seen as troubling in light of the country’s current racial unrest. A second, more pragmatic reason for the delay is the difficulty moving loaned artwork during the pandemic, Feldman said. Almost all of its nearly 200 pieces are loans from 40 institutions and private collectors.

Guston “was a dedicated anti-racist, and they are anti-Ku Klux Klan images used to show evil,” Feldman said of the works. Nonetheless, the museums will consider different approaches to the exhibition, she said, including adding “other voices to consider the work. We are very committed to the project, and we want to do it in a way that respects our audience and can best communicate Guston’s intentions.”

The addition of other perspectives suggests that the museums are trying to avoid the controversy at the Whitney Museum of American Art’s biennial exhibition in 2017, when protesters tried to block White artist Dana Schutz’s painting of Emmett Till, a 14-year-old Black boy who was lynched in 1955. Critics decried what they saw as the White artist’s appropriation of Black suffering. Schutz said she approached the work as a mother.

The Guston postponement was immediately and widely criticized. Mark Godfrey, the curator of the show at the Tate Modern, described the decision as patronizing because it assumes audiences cannot understand difficult work.

“As art museums, we are expected to show difficult art and to support artists. By canceling or delaying, we abandon this responsibility to Guston and also to the artists whose voices animate the catalogue such as Glenn Ligon [and] Tacita Dean,” Godfrey wrote on social media. The exhibition catalogue was published in June.

Darren Walker, the president of the Ford Foundation and one of the National Gallery’s nine trustees, said that attitudes about “incendiary and toxic racial imagery in art” have shifted in recent months and that the museums had to respond.

“An exhibition organized several years ago, no matter how intelligent, must be reconsidered in light of what has changed to contextualize in real time,” he said in a statement Friday. “I agree with the decision to postpone the exhibition so that the museums can ensure that we sensitively and thoughtfully present the works and accompanying public programs. By not taking a step back to address these issues, the four museums would have appeared tone deaf to what is happening in public discourse about art.”

Other art critics and writers criticized the postponement as cowardly and bleak, and several suggested that political considerations were in play. The federally funded National Gallery of Art is beholden to Congress for three-quarters of its $216 million annual budget.

Feldman said there was no pressure from elected officials. Staff attitudes about the show changed in recent months, she said, and those consulted overwhelmingly supported a delay.