Arizona Sen. John McCain has harsh words for his Republican colleagues who want to invoke the “nuclear option” to confirm President Donald Trump’s Supreme Court nominee Neil Gorsuch.

“After 200 years — at least 100 years — of this tradition where the Senate has functioned pretty well, they think it would be a good idea to blow it up,” McCain told reporters Tuesday in remarks reported by NBC News.

“Idiot — no, whoever said that is a stupid idiot,” McCain added.

Senate Republicans have suggested they would use the “nuclear option” to change Senate voting rules to confirm Supreme Court nominee Neil Gorsuch without the 60 votes needed to overcome a filibuster. The rule change would allow Gorsuch to be approved with a simple majority of 51 votes, instead of a super-majority of 60. Republicans hold 52 seats in the Senate, and Democrats hold 48 (including two Independents who caucus with the Democrats).

Then-Senate Majority Leader Harry Reid, a Democrat, used the nuclear option in 2013 to confirm three of former President Barack Obama’s nominees for a federal appeals court. McCain, who also spoke earlier Tuesday to CNN, suggested it would be ironic for Republicans to use the rule after opposing it several year ago.

“I think this is a dark day in the history of the United States Senate,” McCain said on CNN. “It’s going to happen and it’s interesting that Republicans were dead-set against it when my former colleague, Harry Reid, invoked it with the judges. But now it seems to be OK.”

The Senate Judiciary Committee voted to approve Gorsuch on Monday, paving the way for a confirmation vote before the full Senate. Senate Majority Leader Mitch McConnell has said Republicans will do whatever it takes to confirm Gorsuch — a move Trump himself supports.

“If we end up with that gridlock, I would say, if you can Mitch, go nuclear,” Trump said in February.

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