In a highly unusual move, Massachusetts Senator Elizabeth Warren was silenced during a Senate debate Tuesday over the confirmation of Alabama Senator Jeff Sessions for attorney general, after Warren read a 1986 letter written by Coretta Scott King, who was then opposing Sessions for a federal judgeship. This is presiding officer Montana Republican Senator Steve Daines interrupting Warren.

Sen. Elizabeth Warren: “'It has been a long, up-hill struggle to keep alive the vital legislation that protects the most fundamental right to vote. A person who has exhibited so much hostility to the enforcement of those laws'”—

Sen. Steve Daines: “The senator is reminded that it is a violation of Rule 19 of the Standing Rules of the Senate to impute to another senator or senators any conduct or motive unworthy or becoming a senator.”

Sen. Elizabeth Warren: “Mr. President, I don’t think I quite understand. I’m reading a letter from Coretta Scott King to the Judiciary Committee from 1986 that was admitted into the record. I’m simply reading what she wrote.”

Senator Warren was then allowed to continue reading the letter, in which Coretta Scott King writes: “The irony of Mr. Sessions’ nomination is that, if confirmed, he will be given a life tenure for doing with a federal prosecution what the local sheriffs accomplished twenty years ago with clubs and cattle prods. … I believe his confirmation would have a devastating effect on not only the judicial system in Alabama, but also on the progress we have made toward fulfilling my husband’s dream.” After reading the letter, Warren continued speaking, but she was again interrupted—this time by Senate Majority Leader Mitch McConnell.

Majority Leader Mitch McConnell: “Mr. President?”

Sen. Steve Daines: “The majority leader.”

Majority Leader Mitch McConnell: “The senator has impugned the motives and conduct of our colleague from Alabama, as warned by the chair. Senator Warren, quote, said Senator Sessions has used the awesome power of his office to chill the free exercise of the vote by black citizens. I call the senator to order under the provisions of Rule 19.”

Sen. Elizabeth Warren: “Mr. President?”

Sen. Steve Daines: “The senator from Massachusetts.”

Sen. Elizabeth Warren: “Mr. President, I am surprised that the words of Coretta Scott King are not suitable for debate in the United States Senate.”

Senator Warren is now prohibited from speaking for the remainder of the debate over Sessions’s confirmation, after the Senate passed a party-line rebuke Tuesday against her. Her silencing sparked immediate outrage on social media and from other senators. This is California Senator Kamala Harris.

Sen. Kamala Harris: “Mr. President, the suggestion that reciting the words of the great Coretta Scott King would invoke Rule 19 and force Senator Warren to sit down and be silent is outrageous. I move that the senator from Massachusetts be permitted to proceed in order.”