A member of the board that oversees the U.S. Holocaust Memorial Museum wrote a blistering letter to the other board members on Friday condemning the silence of the institution after President Trump’s recent firings and invoking the lead-up to the Holocaust as he warned about the dangers of not speaking out.

In late April, Mr. Trump fired a number of board members appointed by former President Joseph R. Biden Jr., including Doug Emhoff, the husband of former Vice President Kamala Harris, as well as other former senior administration officials.

The firings were widely criticized as an effort to politicize an organization dedicated to educating the world about one of the worst atrocities in history. But the museum’s statement at the time made no mention of the terminations and instead emphasized an eagerness to work with the Trump administration.

Kevin Abel, who was appointed to the museum’s board by Mr. Biden in 2023, wrote in his letter on Friday that Mr. Trump’s “campaign of retribution” had been met with troubling “public silence” by the museum.

Mr. Abel wrote that while it was “understandable” that museum leaders might fear speaking out at the risk of losing funding, it was vital to do so.

“At this juncture of rising threats and a swirling atmosphere of hatred, it is ever more imperative that the United States Holocaust Memorial Museum, the one institution that can most credibly call out the administration’s attack of its Council for what it is, not choose to remain silent,” Mr. Abel wrote, invoking Martin Niemöller’s words “about the danger of not speaking out,” which he noted were “inscribed on the wall of the Museum’s permanent exhibition.”