WASHINGTON (AP) — Republicans are maneuvering to short-circuit an effort by Democrats on the National Labor Relations Board to approve rules that would quicken the pace of union elections.

The GOP member of the labor board is threatening to resign his post, which would deny the board a quorum and quash the entire process. At the same time, the House is poised Wednesday to approve a GOP bill aimed at short-circuiting moves they consider anti-business. That measure is unlikely to go anywhere in the Senate.

The developments are the latest sign of how intensely business groups are opposing any moves that could help organized labor make new inroads at companies that have long opposed unions.

At the labor board, the Democratic majority was set to take up a proposal Wednesday that would simplify procedures and shorten deadlines for holding union elections after employees at a work site gather enough signatures.

But the board's lone GOP member, Brian Hayes, has threatened to quit the agency over his objection to the planned rules, an unprecedented move that would render the board powerless to approve any new measures at all. The board needs at least three members to make any decisions.

If Hayes leaves, only two members — both Democrats — would remain instead of the five members it's supposed to have. Congressional Republicans have blocked President Barack Obama from filling the other two vacancies at the board.

Under current rules, union elections typically take place within 45-60 days after a union gathers enough signatures to file a petition. Republicans contend the new rules could shorten that time to as little as 10 days.

Unions claim companies often abuse current rules to file frivolous appeals, holding up elections for months or even years. But business groups claim the plan would give unions "quickie" elections without leaving employers enough time to respond.

The board's majority has been rushing to approve the new rules before the end of the year, when the term of one of the two Democratic members expires. A modified plan being considered Wednesday is a limited version of more sweeping rules proposed earlier this year. It would not, for example, require employers to provide a list of worker phone numbers and email addresses in voter lists provided to unions.

A final vote on the rules would take place next month, unless Hayes leaves the board.

Hayes has vowed not to participate at the Wednesday meeting and threatened to resign his post over his objection to the rules, according to a letter from the board's chairman, Mark Pearce, circulated last week. Hayes has declined requests for comment.

Union officials have decried Hayes' threat as a bullying tactic that undermines the board.

"We are shocked by the idea that a partisan difference would shut down the workings of a federal agency," said Peter Colavito, director of government relations for the Service Employees International Union.

Minnesota Rep. John Kline, GOP chairman of the House Committee on Education and the Workforce, blamed the board's Democratic majority and called on Pearce to withdraw "his ambush election proposal."

The bitter feud between Hayes and the board's two Democrats is the latest sign of how polarizing the debate over union rights has become. Board members often quarrel over policy differences, depending on which political party is in the majority. But labor experts say a board member has never resigned for the sole purpose of preventing a vote.

"As far as I'm aware, it's unprecedented," said William Gould, a former NLRB chairman during the Clinton administration and now a professor at Stanford Law School. "The board has become more polarized, but this takes it to a different level entirely."

In the House, meanwhile, Republicans are expected to pass a bill that would override any changes to NLRB election rules. The measure would delay any vote on a union for at least 35 days after a petition is filed.

The bill would also overturn a recent board ruling that made it easier for smaller groups of workers within companies to organize bargaining units. Business groups claim so-called "micro-bargaining unions" would allow unions to cherry-pick certain departments or employees within a company.

"Congress must act now to thwart the NLRB's radical regulatory maneuvers," said David French, a vice president for government relations at the National Retail Federation, the world's largest retail trade group.

The federation, whose members include J.C. Penney, Best Buy Co. and Macy's Inc., claims the board's proposed rules would limit workers access to "information needed to make an informed decision about union representation."

California Rep. George Miller, top Democrat on the House Education and the Workforce committee, has denounced the measure as an "anti-worker, anti-family bill" that would undermine worker rights.

The bill is not expected to go far in the Senate, where Democratic leaders are not likely to bring it to a vote.