Updated

The Obama administration wants quick confirmation of five nominees to fill seats on the National Labor Relations Board, which has been mired for months in a controversy over recess appointments.

But Republicans were not expected to make it easy Thursday when the nominees appear at a Senate confirmation hearing.

An impasse could soon leave the board inoperable because the term of the board's current chairman, Mark Pearce, expires in August. If no new nominees are confirmed by then, the board will not have enough members to operate. It has only three members now, the bare minimum to conduct business.

The prospect of a crippled NLRB has angered labor unions, which count on the agency to resolve worker complaints of unfair labor violations and issue key legal decisions on labor-management disputes.

The board has been in limbo since January, when a federal appeals court said the president violated the Constitution by filling vacancies on the board without Senate confirmation. The administration is appealing the decision to the Supreme Court, but in the meantime, hundreds of its decisions have been called into question.

Republicans claim the board has no legitimacy to act and have demanded the two recess appointees -- Sharon Block and Richard Griffin -- step down. They have declined.

President Obama has defied Republicans by nominating Griffin and Block to full terms on the board. Obama also has renominated the board's chairman to another full term. All three are Democrats.

The other two nominees, lawyers Harry I. Johnson III and Philip A. Miscimarra, are Republicans. The White House hoped the bipartisan package would pass muster with Republicans, but GOP leaders in the Senate already have indicated they will oppose Griffin and Block.

The labor board has been caught in a nonstop political tug of war for years. Republicans and their allies in the business community have complained that the board is issuing too many pro-unions decisions. Obama claims he was forced to make recess appointments because some Senate Republicans vowed to block confirmation of any new NLRB members.

Unions say the president is entitled to appoint a majority of members who are sympathetic to labor, just as Republican presidents have installed business-friendly majorities when they occupied the White House.

After Thursday's hearing, the Senate Health, Education, Labor and Pensions Committee was expected to vote on the nominees next week. While the committee's Democratic majority was expected to endorse the nominees, Republicans were likely to demand 60 votes for a full vote to proceed on the Senate floor.