The Senate just went "nuclear."

Senate Majority Leader Harry Reid announced a proposal on the Senate floor Thursday morning tp drastically change Senate rules on the controversial filibuster. His proposal requires only a simple majority vote to approve executive and judicial nominees.

The Senate passed the measure by a 52-48 vote Thursday afternoon. All but three Democrats voted in favor of the major rules change, which now allows most presidential nominees to get an up-or-down vote.

This doesn't apply to Supreme Court nominees or the passage of ordinary legislation.

Senate rules required a 3/5 majority to confirm executive and judicial nominees. Recently, Republicans have blocked three of President Barack Obama's nominees to the U.S. Court of Appeals for the D.C. Circuit, as well as Rep. Mel Watt (D-N.C.) to head the Federal Housing Finance Agency (which oversees Fannie Mae and Freddie Mac). The mass blockade of judges, Democrats say, left them with no choice but to pull the nuclear trigger.

"Is the Senate working now? Can anyone say the Senate is working now? I don't think so," Reid said on the Senate floor.

"It's time to change the Senate before this institution becomes obsolete," he added.

Responding to Reid on the Senate floor, Minority Leader Mitch McConnell said that Reid was engaging in a "fake fight" over Senate rules to distract from the disastrous rollout of the Affordable Care Act.

He also offered a blunt warning.

"You will regret this and you may regret it a lot sooner than you think," he said, hinting that Reid should think about a possible GOP takeover of the Senate in 2015.

President Barack Obama, in a statement from the White House Thursday afternoon, said that he supported the rules change.

Minutes after the vote to change the rules, the Senate voted to advance the nomination of Patricia Millet, one of the D.C. Circuit Court judge potentials, by a 55-43 vote. Before the rules change, she would've needed 60 votes to move through.

Democrats were confident leading up to the big vote that they had enough Democratic support for the drastic rules change — talks of which have popped up in the Senate two other times this year.

One Democratic Senate aide on Wednesday pointed to members of the "old guard" who have previously been skittish about going nuclear — Sens. Patrick Leahy (D-Vt.), Barbara Boxer (D-Calif.), and Dianne Feinstein (D-Calif.) — coming around this time, because they've had enough.

"We feel really good about the count," the aide told Business Insider.

This isn't the first time "nuclear" talk has flared up in the Senate this year. Most recently in July, the Senate appeared on the brink of "going nuclear," only to end up with a familiar last-minute deal. But the aide said that the only plausible way out of a confrontation this time would be Republicans giving in to all three D.C. Circuit Court nominations plus Watt, which would have amounted to a dramatic reversal from Republicans.