Ruth Marcus, who has been a columnist for The Washington Post for nearly 20 years, resigned today in what she said was a protest of the decision to kill a piece critical of owner Jeff Bezos‘ overhaul of the opinion section.

“Jeff’s announcement that the opinion section will henceforth not publish views that deviate from the pillars of individual liberties and free markets threatens to break the trust of readers that columnists are writing what they believe, not what the owner has deemed acceptable,” Marcus wrote in a letter to Bezos and the CEO of the Post, Will Lewis.

She added, “Will’s decision to not run the column that I wrote respectfully dissenting from Jeff’s edict — something that I have not experienced in almost two decades of column writing — underscores that the traditional freedom of columnists to select the topics they wish to address and say what they think has been dangerously eroded.” The New York Times first obtained her letter.

Marcus is the latest high-profile Post staffer to exit as Bezos has exercised more control over the news outlet. In October, Bezos killed a planned editorial page presidential endorsement of Kamala Harris. Last month, he announced that the editorials would focus on “personal liberties and free markets,” and that “viewpoints opposing those pillars will be left to be published by others.”

David Shipley, the opinion editor, departed the Post following the announcement. The Post’s former executive editor, Martin Baron, was sharply critical of Bezos’ announcement, putting it into context of other moves seen as trying to ingratiate himself with Trump. Bezos attended Trump’s swearing in ceremony and Amazon reportedly paid $40 million for a documentary on Melania Trump.

Marcus has been with the Post since 1984. She joined the editorial board in 2003 and started the column in 1986.

A Post spokesperson said, “We’re grateful for Ruth’s significant contributions to The Washington Post over the past 40 years. We respect her decision to leave and wish her the best.”