Massachusetts Sen. Elizabeth Warren, one of the many Democrats running for president in 2020, officially called for ending the Senate filibuster on Friday, condemning it as a historic "tool to block progress on racial justice" which is currently being used by the far right to "block progress on everything."

"I've watched Republicans abuse the rules when they're out of power, then turn around and blow off the rules when they're in power," Warren said in a campaign email to supporters.

The filibuster was originally used by senators to control the Senate floor in order to prevent a vote on a bill. The most famous filibuster in popular imagination is likely the one carried out by Jimmy Stewart in "Mr. Smith Goes to Washington." The longest real-life filibuster was carried out by South Carolina Sen. Strom Thurmond, who filibustered for 24 hours and 18 minutes to stop a vote on the 1957 Civil Rights Act.

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Warren argued that the filibuster has a "long, ugly" history, a fact that is acknowledged by the Senate's own website.

"Filibusters were particularly useful to Southern senators who sought to block civil rights legislation, including anti-lynching legislation, until cloture was invoked after a 60 day filibuster against the Civil Right Act of 1964," the site notes. Cloture is the device used by the Senate to end debate -- it originally required a two-thirds majority of the Senate. A decade later, in 1975, the Senate dropped that number to 60 votes.

Now, the filibuster isn't so much an endless speech on the floor so much as the threat of an endless speech on the floor. If there aren't 60 votes to support moving forward with a bill in the Senate, it'll come to a halt. There are 53 GOP senators, well short of the 60-vote threshold.

In recent years, a "nuclear option" has been used to get around the filibuster. Then-Sen. Majority Leader Harry Reid first used it in 2013, when Republican senators refused to approve President Obama's judicial nominees. That opened the door to Sen. Majority Leader Mitch McConnell's use of the nuclear option to confirm President Trump's nomination of Neil Gorsuch to the Supreme Court.

On Wednesday, the Senate went "nuclear" again, voting 51-48 Wednesday afternoon to change its own rules and slash debate time for some nominees from 30 hours to two hours, paving the way to fast-track certain Trump picks.

The Massachusetts senator noted that even recently, the filibuster had been used to block the passage of an anti-lynching bill, which was signed into law in 2018. The bill had first been introduced in 1918, and again in 1922, but was killed in the Senate thanks to a filibuster. The bill was blocked from passage over 200 times.

"An entire century of obstruction because a small group of racists stopped the entire nation from doing what was right," Warren wrote. "For generations, the filibuster was used as a tool to block progress on racial justice. And in recent years, it's been used by the far right as a tool to block progress on everything."

Warren also condemned Republicans in the Senate for manipulating the rules to block President Obama's judicial nominees, and then changing them to quickly push through President Trump's nominations.

"Republicans spent years -- years -- exploiting the rules to slow down or block President Obama's mainstream judges and Executive nominees. But now that they're in power, they're unilaterally changing those rules to speed up and ram through President Trump's extreme nominees," Warren wrote, linking to a petition for supporters to sign to get rid of the filibuster.

Warren maintains that there is no mention of the filibuster in the Constitution, and because it was created by the Senate, it can be undone by the Senate. The filibuster was first used in the Senate by 1837.

"If we campaign and win on big ideas, but can't pass any of them in 2021 -- even with majorities in Congress -- the American people will think our government is just as rigged for the wealthy and well-connected as before," Warren said. "When we win this election, we will make the changes we need in this country."

Warren floated the idea of eliminating the filibuster in an interview with "Pod Save America" in February. She has called for other massive structural changes in American government, such as getting rid of the Electoral College.