A lack of vision and transparency at the Hirshhorn has driven out another museum higher-up: This morning the Washington Post reported that Hirshhorn’s Board of Trustees Chair Constance Caplan resigned on Monday. In her resignation letter, Caplan cites “the contentious manner and lack of inclusiveness with which a number of trustees and staff associated with the Hirshhorn and the Smithsonian have behaved over the past year,” as well as “a regression to programming that imitates a predictable pattern at many other modern and contemporary museums.”

Caplan is the third board member the Hirshhorn has lost since May. Hirshhorn Director Richard Koshalek resigned from the museum in late May, attributing his decision to frustration with a lack of support for his initiatives, including the museum’s contested bubble project. The balloon was officially scrapped in early June.

In her letter, Caplan criticizes a disturbing pattern of behavior on the Hirshhorn’s board, such as “shocking breaches in confidentiality” and “inappropriate interruptions during Board meetings.” She also says the board wasn’t afforded a chance to review Koshalek’s replacement, “a routine courtesy at other leading institutions.” Acting Director Kerry Brougher took the reins on June 30.

But Caplan says it’s the museum’s unambitious vision that really cinched her decision to leave: “I certainly understand the serious financial challenges and constraints now at hand; I also deeply agree that trustees should not be involved in the artistic decisions that are clearly the purview of the director and staff,” Caplan writes. “Yet via recent communications from the Museum that simply focus on exhibitions and operations (essential as these are), I see the Hirshhorn abruptly regressing from the vision of serving as ‘the nation’s museum of contemporary art’—-a vision especially appropriate to its splendid, unique setting—-retreating at a time when precisely because of the challenges at hand, this larger role is more important than ever.”

The Washington Post has Caplan’s whole resignation letter.