WASHINGTON — In a move that Sen. Lamar Alexander (R-Tenn.) called “the most important and most dangerous restructuring of Senate rules since Thomas Jefferson wrote them,” Majority Leader Harry Reid (D-Nev.) pushed the button on the long-threatened “nuclear option” today to require a simple majority to move forward President Obama’s judicial nominees.

There were three Democratic defectors — Sens. Carl Levin (D-Mich.), Mark Pryor (D-Ark.) and Joe Manchin (D-W.Va.) — on the rules change, which came to the floor over the block of three judges intended for the D.C. Circuit Court of Appeals.

Levin said he was being consistent with his previous opposition when a Republican majority flirted with the nuclear option in 2005.

“Since its creation, the United States Senate has been uniquely committed to protecting the rights of minorities. It has done so in part through its rules governing debate. Its rules protect the right of members to speak until a super-majority is ready to end debate and to proceed to a vote on the matter before it. Matters are then decided by a majority vote, except for treaties, veto overrides and certain points of order,” Levin said on the floor in a lengthy objection to the rules change.

“Today, we once again are moving down a destructive path. The issue is not whether to change the rules. I support changing the rules to allow a president to get a vote on nominees to executive and most judicial positions. This is not about the ends, but means. Pursuing the nuclear option in this manner removes an important check on majority overreach which is central to our system of government. As Senator Vandenberg warned us, if a Senate majority decides to pursue its aims unrestrained by the rules, we will have sacrificed a professed vital principle for the sake of momentary gain.”

Levin, who is retiring in 2015 after six terms, reminded his colleagues of what then-Sen. Joe Biden (D-Del.) said during the GOP-era debate: “The nuclear option abandons America’s sense of fair play. It’s the one thing this country stands for. Not tilting the playing field on the side of those who control and own the field.”

Pryor, who faces a re-election fight in 2014, said the use of the nuclear option “could permanently damage the Senate and have negative ramifications for the American people.”

“During my time in the Senate, I’ve played key roles in the Gang of 14 and other bipartisan coalitions to help us reach common-sense solutions that both sides of the aisle can support,” Pryor said. “This institution was designed to protect—not stamp out—the voices of the minority.”

Manchin said he’d proposed a compromise that would require “greater consideration for nominees whose posts outlasted the president.”

“I was willing to support modest changes to make the system more efficient, but my proposal was rejected,” he said. “I voted against the rules changes today because they simply went too far. I firmly believe that the filibuster is a vital protection of the minority views and exactly why the framers of our Constitution made the Senate the ‘cooling saucer.’”

Most Dems hailed the move, with Sen. Tom Harkin (D-Iowa) praising Reid on the floor “for leading us into the 21st century.”

“I’ve waited 18 years for this moment,” Harkin giddily added.

The rules change applies to nominees, not legislation, though Obama mingled that into his statement praising what Reid did — raising a more realistic threat of the nuclear option on hot-button issues where Reid has threatened to use it in the past.

“It’s no secret that the American people have probably never been more frustrated with Washington, and one of the reasons why that is, is that over the past five years we’ve seen an unprecedented pattern of obstruction in Congress that’s prevented too much of the American people’s business from getting done,” he said in the press briefing room this afternoon, blaming “arcane procedural tactics” for why Americans are so unhappy.

Obama charged that Republicans have “blocked legislation that might create jobs,” help “women fighting for equal pay” and “striving young immigrants trying to earn citizenship,” and pass “common-sense” gun-control laws in a way that’s “harmful to our democracy.”

“A simple majority vote no longer seems to be sufficient for anything, even routine business through what is supposed to be the world’s greatest deliberative body,” he said. “Today’s pattern of obstruction, it just isn’t normal… for the sake of future generations we can’t let it become normal.”

“Public service is not a game. It is a privilege. And the consequences of action or inaction are very real. The American people deserve better than politicians who run for election telling them how terrible government is and then devoting their time in elected office to trying to make government not work as often as possible.”

The rules change comes in time to help Obama get his Fed chief nominee, Janet Yellen, through the Senate as an increasing number of lawmakers have been coming out against her confirmation — including, this afternoon, Manchin.

It also will help move forward the president’s Federal Housing Finance Agency nominee Rep. Mel Watt (D-N.C.), who didn’t clear a 60-vote cloture threshold late last month, and Department of Homeland Security nominee Jeh Johnson.

Alexander told reporters after the nuclear vote that the move is “like the Red Sox falling behind in Boston, and saying to the Cardinals, ‘Well, we’re the home team, so we’ll just add a few innings until we could score some runs.'”

“This is a Senate without rules. And it’s done based upon the flimsiest of excuses. The argument is that filibusters were used to deny seats to presidential nominees,” the senator continued. “In the history of the Senate, the number of Supreme Court nominees who’ve been denied their seat by filibuster is zero, with a little asterisk for Abe Fortis, which was an LBJ maneuver. The number of district judges denied their seat by filibuster is zero. The number of cabinet members denied their seat by filibuster is zero.”

“The number of circuit judges denied their seat by filibuster is five Democrats and five Republicans, all because Democrats, for the first time in 2003, just the time I was coming to the Senate, filibustered 10 of President Bush’s judges, and that was the first time in history.”

Minority Leader Mitch McConnell (R-Ky.), who warned Reid that what goes around could come around if the GOP retakes the Senate, said “it’s a time to be sad about what’s been done to the United States Senate, the greatest deliberative body in the world.”

McConnell wouldn’t answer “hypothetical” questions about how he could take revenge, but added, “I will say this: The American people are deeply disturbed by this administration and this Senate.”

At a press conference with Democratic leaders, Reid defended his move, claiming “our founding fathers were very clear in what they thought there should be super-majorities.”

“Simple fairness. The changes we made today will apply equally to both parties. When a Republican’s in power, these changes will apply to them as well. That’s simple fairness,” he said. “…Everyone know what is going on is absolutely unfair and wrong and I’m glad we changed it. It is a day of freshness for this great country of ours.”

Majority Whip Dick Durbin (D-Ill.) summed up McConnell’s opposition as: “The notion of filibustering judges was a Democratic idea. We — they abused it, and we did, too.”

“We’ve put the government back in business, thank goodness,” Durbin said.

Sen. Jeff Flake (R-Ariz.), though, accused Democrats of finally dropping the bomb to avert eyes from another disaster, a sentiment quickly shared by many of his colleagues.

“It’s a sad day in the Senate when Democrats are willing to ignore 225 years of precedent to distract attention away from the failures of Obamacare,” said Flake.

“The Democrats’ attempt to pivot at a time when we should be focused on protecting the American people from dropped healthcare coverage makes their true motives clear,” said Minority Whip John Cornyn (R-Texas). “They will do anything to take the attention off the failure that is Obamacare, even if it means breaking the rules of the Senate in a raw exercise of partisan political power.”

Sen. Tim Scott (R-S.C.) warned that the rules change “carries implications Democrats are going to have to live with when Republicans retake the Senate.”

“It is also unfortunate that Senator Reid and Senate Democrats have developed amnesia in regards to how they acted when Republicans were in the majority,” Scott said. “While they held up nominations for up to a thousand days under President Bush, Democrats have now decided to invoke the nuclear option over nominees for a court that doesn’t even have the workload to keep the judges it has busy.”

Sen. John McCain (R-Ariz.) warned that the last remaining scraps of bipartisanship left in the Senate are now officially on life support.

“This changes everything, this changes everything,” McCain told reporters, adding that the nuclear option “puts a chill on the entire United States Senate.”

“I have reached out to them. I spent an hour in Harry Reid’s office. Come on. I reached out until my arms ache,” McCain said. “They are governed by these hard over, newer members of Democratic senators who have never been a minority, who are primarily driving this issue and they succeeded — and they will pay a very, very heavy price for it.”

“This is a power grab,” Alexander said. “It’s Obama II. It’s another partisan, political maneuver, to permit the Democratic majority to do whatever it wants to do. In this case, it’s to advance the president’s regulatory agenda. The only cure for it that I know is an election.”