At a CNN climate change forum, the California senator said she agreed with former Democratic presidential candidate Jay Inslee in opposing the Senate procedure.
“The future of our country is sacrificed at the altar of the filibuster," the former Senate majority leader wrote in a New York Times op-ed.
The former Senate majority leader said it wasn't a matter of if the legislative tactic would end but "a question of when."
Senators may block a key defense bill to force President Trump to get congressional approval for a war on Iran.
It involves blowing up an arcane procedural rule in the Senate known as reconciliation.
In an interview with HuffPost, presidential candidate Sen. Bernie Sanders (I-Vt.) explained why he is skeptical about getting rid of the filibuster.
"You should be a little bit nervous if Donald Trump supports it," the 2020 presidential candidate said.
The 2020 presidential candidate announced her stance Friday at a conference with a civil rights group.
The 2020 Democratic presidential contender running on a message of compromise and bipartisanship is taking a second look at the filibuster.
The longtime senator often defended the filibuster when it benefitted him, but he hasn't always been a fan of the chamber's supermajority requirement.