In doing so, McConnell asserted his control over a chamber that is increasingly at risk of veering from normal protocol. But he also sparked a dramatic backlash, with accusations of sexism and selective use of an obscure Senate rule bouncing around social media for much of today.
Democratic criticized McConnell, particularly for this statement lyesterday: "She was warned. She was given an explanation. Nevertheless, she persisted."
Outside of the Senate, liberals gleefully thanked McConnell for elevating Warren, one of the Democratic Party's biggest stars, and handing her a slogan for a potential 2020 presidential bid.
"I think Leader McConnell owes Senator Warren an apology," said Senator Bernie Sanders in a Senate floor speech today. He and other Democrats were particularly chagrined that a Senate rule could be invoked to prevent a member from criticising someone who is up for confirmation before the body.
Senator Chris Murphy tweeted: "Rules against criticizing other Senators cannot apply when you are DEBATING THE NOMINATION OF A SENATOR!"
The flare-up began as Warren attempted to read a statement by Coretta Scott King, the late widow of the Rev. Martin Luther King in opposition to Sessions' 1986 nomination for a slot as a federal district court judge. The letter accused Sessions of using his role at the time as a US Attorney to undermine voting rights.
"Mr Sessions has used the awesome power of his office in a shabby attempt to intimidate and frighten elderly black voters," King wrote.
Several Democrats took to the Senate floor to re-read a portion of that statement in solidarity with Warren.
"Still banned from floor, but spoke w/ civil rights leaders this AM to say: Coretta Scott King will not be silenced," Warren told her more than 1.8 million followers on Twitter today.
Republicans were not happy with Warren's actions. In an interview on Fox News, Senator Ted Cruz accused his Democratic colleague of advancing false claims about Sessions and sought to remind Americans that southern Democrats were "the party of the Ku Klux Klan" and spearheaded segregation laws decades ago.
"The Democrats are angry and they're out of their minds. ... They're just foaming at the mouth practically," Cruz said.
Cruz once called McConnell a liar on the Senate floor, and he was not rebuked.
Senate Minority Leader Charles Schumer argued that Republicans were being hypocritical. They had no qualms about silencing Warren, he argued, even as they have declined to rebuke Trump for aggressively lobbing insults at his critics.
"My Republican colleagues can hardly summon a note of disapproval for an Administration that insults a federal judge, tells the news media to shut up, offhandedly threatens a legislator's career and seems to invent new dimensions of falsehood each and every day," Schumer said. "I hope that this anti-free speech attitude is not traveling down Pennsylvania Ave. to our great chamber."