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Jeff Merkley.
"The dark deed is done," Merkley tweeted. "McConnel has just put a knife into the heart of our We the People republic."
The "nuclear" option - rewriting the Senate rules to kill the filibuster on Supreme Court nominees by a simple majority vote- was utilized to clear the path for Judge Neil Gorsuch, President Donald Trump's nominee for the high court, to be confirmed.
In an initial procedural vote, Republicans failed to clear a 60-vote threshold to move forward with Gorsuch's confirmation, prompting McConnell to take the step.
The vote to change the rules was 52 to 48, split along party lines. After the rules change, senators voted 55 to 45 to advance Gorsuch's confirmation to a final vote on Friday.
Democrats have employed the tactic before. Harry Reid, the former Senate majority leader, used it in 2013 to assist in the confirmations of President Barack Obama's judicial and executive nominees.
Merkley, who spoke on the Senate floor for 15 hours starting Tuesday night and continuing into Wednesday morning in protest of Gorsuch, struck a different chord after that 2013 instance.
"Thank you for your leadership," Merkley wrote in a retweet of Reid. Reid had written: "Thanks to all of you who encouraged me to consider filibuster reform. It had to be done."