After thousands of high-profile artists and curators signed an open letter expressing solidarity with Palestinians and supporting a ceasefire in Gaza, published in the magazine Artforum on October 19, the public pushback was swift. The following day, the magazine posted a public response signed by prominent gallerists denouncing the original letter as “one-sided.” Behind the scenes, however, powerful art dealers and gallerists who control the cultural and monetary tides of the art world began a private campaign to force some of the biggest names on the letter to retract their support, according to a half dozen sources, including letter signatories...