WASHINGTON — Senate Republicans will not support five nominees to the National Labor Relations Board, they said Thursday, raising the possibility the agency could be mostly inoperable later this year.
The board has been under a cloud since January, when an appeals court said the president violated the Constitution by filling vacancies through so-called recess appointments without Senate confirmation.
An impasse over the latest nominees could pose broader problems. The five-member board needs at least three sitting members to conduct business. It has three now, but the term of its chairman, Mark Pearce, expires in August.
At a Senate confirmation hearing for the nominees, GOP lawmakers renewed their assertion that the board has no authority to act while the two recess appointees — Sharon Block and Richard Griffin — are serving. Republicans expressed further annoyance that President Obama is including Block and Griffin in his slate of five nominees for full terms.
Senator Lamar Alexander of Tennessee, senior Republican on the Health, Education, Labor, and Pensions Committee, said the White House has shown ‘‘a troubling lack of respect for the constitutional separation of powers and for the Senate’s role of advice and consent.”
Griffin and Block said they decided to remain on the board because they took an oath to serve. They said it was proper to continue serving until the Supreme Court steps in.
Democrats accused Republicans of obstructionism because the GOP and its allies in the business community have been unhappy with some of the union-friendly decisions issued by the board.
‘‘This is about complete obstructionism because the minority senators don’t like the agencies, and they don’t like the work these agencies do,’’ said Senator Elizabeth Warren, Democrat of Massachusetts.