In his resignation letter, Marcus states that the newspaper refused to publish a column where she criticizes The Washington Post's owner, Amazon billionaire Jeff Bezos, decision that the editorial pages will no longer publish opinions that contradict "personal freedoms and free markets".
Ruth Marcus writes that she expressed her dissenting opinion in a respectful manner but still saw her column "killed", which has never happened to her before.
"The traditional freedom for columnists to choose the topics they want to take up and say what they think has been eroded in a dangerous way", she writes.
Even the editorial page editor David Shipley has resigned.
