The Democrat majority in the Senate on Thursday pushed through a major rules change, one that curbs the power of the Republican minority to block President Barack Obama's nominations for high-level judgeships and cabinet and agency officials. The move was certain to only deepen the partisan divide that has crippled passage of legislation.

Infuriated over repeated Republican blocks of Obama candidates for critical judgeships, Senate Majority Leader Harry Reid took the dramatic step, calling it "simple fairness" because the change would work in Republicans' favor whenever they regain the White House and a Senate majority.

Current Senate rules allowed any one member of the chamber, using a tactic called a filibuster, to block a president's nominations unless 60 of the 100 Senators vote to move forward with the nomination. The 60-vote threshold has proven difficult for Democrats to assemble given they hold only a 55-45 edge over the Republicans in a hyper-partisan political climate and stalemated Congress.

"The gears of government have to work," Obama said shortly after the Senate vote. In a brief White House appearance to congratulate his fellow Democrats, Obama complained that the old filibuster rule allowed opposition senators to avoid voting their conscience on legislation on which a yes vote could put them under attack from the far rightwing of the party.

Known as the "nuclear option," Reid said the rules change would help break partisan gridlock that has sent voter approval of Congress to record lows. He forced a vote on requiring only 51 votes to end a filibuster. The change would not end the 60-vote threshold for overcoming blocking action for Supreme Court nominees or legislation.

The change is the most far-reaching to filibuster rules since 1975, when a two-thirds requirement for cutting off filibusters against legislation and all nominations was eased to today's three-fifths, or 60-vote, level. It would make it harder for the opposition party to block presidential appointments.

The latest battle is over Obama's choices to fill three vacancies at the U.S. Court of Appeals for the District of Columbia Circuit. Since Oct. 31, Republican filibusters derailed the president's nominations of District Judge Robert L. Wilkins, law professor Cornelia Pillard and attorney Patricia Millett for those lifelong appointments. The D.C. Circuit Court is viewed as second only to the Supreme Court in power because it rules on disputes over White House and federal agency actions. The circuit's eight sitting judges are divided evenly between Democratic and Republican presidential appointees. Three seats are vacant.

"They have decided that their base demands a permanent campaign against the president and maximum use of every tool available," said Democrat Sen. Jeff Merkley, a leading advocate of revamping filibuster rules that have been used a record number of times during the Obama presidency. He said Republican tactics are "trumping the appropriate exercise of advice and consent."

Republicans said they are weary of repeated Democratic threats to rewrite the rules. They say Democrats similarly obstructed some of President George W. Bush's nominees and argue that the D.C. Circuit's caseload is too low, which Democrats reject.

"I suspect the reason they may be doing it is hoping Republicans overreact, and it's the only thing that they could think of that would change the conversation about Obamacare," said Republican Sen. Lamar Alexander, using the nickname for Obama's troubled health care law. "But we're not that dumb."

Reid use of the nuclear option procedural move would allow him to change the filibuster rule with just 51 votes, meaning Democrats could push it through without Republican support. Senate rules are more commonly changed with 67 votes.

Nomination fights are not new in the Senate, but as the hostility has grown the two sides have been edging toward a collision for much of this year.

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Associated Press writer Alan Fram contributed to this report.