In a near-empty chamber, Warren rose in the evening in opposition to Sessions, the Republican senator from Alabama. She cited some of the issues — including accusations that he targeted black voters in an investigation — that stifled his nomination for a federal judgeship in the 1980s.

The striking 49-to-43 vote, which occurred along party lines, marked yet another setback for decorum in a chamber that has long considered itself the world’s greatest deliberative body. It also immediately made the Massachusetts Democrat a hero of the left, with a Twitter hashtag #LetLizSpeak quickly going viral.

WASHINGTON — Senator Elizabeth Warren was ruled in violation of Senate rules late Tuesday night after quoting from a decades-old letter written by Martin Luther King Jr.’s widow — a rare rebuke that silenced Warren from further debate on the nomination of Senator Jeff Sessions as attorney general.


“He has made derogatory and racist comments that should have no place in our justice system,” she said. “To put Senator Sessions in charge of the Department of Justice is an insult to African-Americans.”

She read a 1986 letter from Coretta Scott King, the widow of Martin Luther King Jr., who had accused Sessions of “a shabby attempt to intimidate and frighten elderly black voters.”

“Mr. Sessions has used the awesome power of his office to chill the free exercise of the vote by black citizens in the district he now seeks to serve as a federal judge,” King wrote to the Senate Judiciary Committee, then chaired by Strom Thurmond of South Carolina.

Earlier during her speech, Warren also quoted from Senator Edward M. Kennedy — who had called Sessions a “disgrace to the Justice Department.” She was issued a warning.

The quotes from King prompted Senate majority leader Mitch McConnell to come to the Senate floor and call for a vote that Warren was violating Senate rules.


“The senator has impugned the motives and conduct of our colleague from Alabama, as warned by the chair,” McConnell said. “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 am surprised that the words of Coretta Scott King are not suitable for debate in the United States Senate,” Warren responded.

She asked for permission to continue, but McConnell objected.

She was accused of violating the Senate’s “Rule 19,” which says that senators are prohibited from “directly or indirectly, by any form of words impute to another senator or to other senators any conduct or motive unworthy or unbecoming a senator.”

“I’ve been red-carded; I’ve been thrown out of the game,” Warren said in a phone interview with the Globe, stepping off briefly from the Senate floor where she continued to sit although she was no longer allowed to speak.

She said she had not expected to get rebuked for her speech.

“I thought what Senator Kennedy said back then would be fair game,” she said of her reading of Kennedy’s 1986 statement. “At that time it got both Republican and Democratic votes against Jeff Sessions.

“And I read Coretta Scott King’s letter that described what Jeff Sessions had done as US attorney and the impact it had had on voting rights for people in Alabama,” Warren continued. “I thought that letter was moving and entirely appropriate to be read on the floor of the Unites States Senate.”


Warren said she was warned that she was “out of line . . . then I was gaveled down and forced to shut up when I read Coretta Scott King’s letter. No I did not go into tonight expecting that.”

Warren said she had “no idea” why McConnell chose to shut her down, unless it was “to make clear that the Republicans do not want the public talking about Jeff Sessions’s record. That’s the only possible reason.”

Warren said she hopes that everyone will read the letter she was cut off from reading.

“It’s a powerful letter and it describes a moment in our history that is important to every one of us today,” she said.

Around 11 p.m., Warren continued her protest by reading the King letter just outside the Senate chamber, which she streamed live on Facebook.

The debate in the Senate was yet another sign of how toxic the political atmosphere has become, particularly in confirming President Trump’s Cabinet members. Democrats don’t have enough supporters in the Senate to stifle the confirmations, but they have attempted instead to delay votes.

After the vote upholding the finding that she had violated Senate rules, McConnell said that Warren ignored all the warnings to stop attacking Sessions.

“Senator Warren was giving a lengthy speech. She had appeared to violate the rule. She was warned. She was given an explanation,” he said. “Nevertheless, she persisted.”


Senator Kamala Harris, a newly elected California Democrat, called the vote to hold Warren in violation of the rule outrageous and asked the Senate to allow her to speak during debate.

That vote failed.

Democrats also seized on the episode on social media.

Dan Pfeiffer, a former senior aide to Barack Obama, said on Twitter: “Going out on a limb here but shushing @elizabethforma to prevent her from reading the words of Coretta Scott King just might backfire”

Senate Democrats pointed to recent instances — including when Senator Ted Cruz last year accused McConnell of “a simple lie,” or when Senator David Perdue last week accused minority leader Charles Schumer of “a tear-jerking performance over the past weekend belongs at the Screen Actors Guild awards” — that did not trigger a similar rebuke.

“I never ever saw a time when a member of the Senate asked to put into the record a letter — especially by a civil rights icon — and somebody objected,” said Senator Patrick Leahy, the Vermont Democrat and the longest-serving member of the Senate.

“Don’t let the Senate turn into something it’s never been before,” he added. “I would hope that cooler heads prevail.”

Republicans countered that Warren broke a rule, and should be punished.

“We have rules around here, the rules are very clear that you don’t impugn another senator. you can’t do it with words, and you can’t do it with citings,’’ said Senator Jim Risch, a Republican from Idaho. “It is not OK. it’s a violation of the rules.”


It also triggered a series of speeches about how far the dialogue in the Senate had fallen.

“Everything doesn’t have to lead to a gut fight on the floor,” said Senator Orrin Hatch, a Utah Republican. “But that’s where we’re going. . . . We’ve got to grow up.”

Read Warren’s Twitter comments on the incident:

I spoke out about @SenatorSessions – until @SenateMajLdr McConnell decided to silence me. https://t.co/qbty7x0iLl — Elizabeth Warren (@SenWarren) February 8, 2017

I will not be silent about a nominee for AG who has made derogatory & racist comments that have no place in our justice system. — Elizabeth Warren (@SenWarren) February 8, 2017

I will not be silent while the Republicans rubber stamp an AG who will never stand up to the @POTUS when he breaks the law. — Elizabeth Warren (@SenWarren) February 8, 2017

Tonight @SenateMajLdr silenced Mrs King's voice on the Sen floor - & millions who are afraid & appalled by what's happening in our country. — Elizabeth Warren (@SenWarren) February 8, 2017

Victoria McGrane can be reached at victoria.mcgrane@globe.com. Follow her on Twitter@vgmac. Matt Viser can be reached atmatt.viser@globe.com. Follow him on Twitter @mviser.