All Senate Republicans wrote President Barack Obama on Thursday, demanding he not use a recess appointment to fill spots on a labor board.

Sens. Orrin Hatch (R-Utah) and John McCain (R-Ariz.), joined by all of their Republican colleagues in the Senate, warned the president against using his recess appointment powers to name Craig Becker to the National Labor Relations Board (NLRB).

"We are writing to urge you to not act in contravention of the bipartisan Senate vote against the nomination of Craig Becker to be a Member of the National Labor Relations Board (NLRB) through a recess appointment," the senators said. "To do so would disregard the Senate's constitutional responsibility of advice and consent."

Becker's nomination came up before the Senate in early February, but fell eight senators in a procedural vote. Two Democrats -- Sens. Blanche Lincoln (D-Ark.) and Ben Nelson (D-Neb.) -- voted against the nomination, as did Sen. Scott Brown (R-Mass.), in his first major vote as senator.

Labor groups have been optimistic that Obama would use the power of recess appointment to name Becker, a controversial labor attorney, to the NLRB. Republicans and business groups have said they fear that Becker's addition to the board would make it a back channel to implementing elements of the Employee Free Choice Act (EFCA, or "card check").

Sen. Tom Harkin (D-Iowa) sent signals Wednesday that he thinks Obama will use the power when Congress breaks this weekend for two weeks in observance of the Passover and Easter holidays, as well as for some district work time.

The NLRB has been operating with only two members for years now, a topic that has forced litigation before the Supreme Court as to whether the board's ruling are valid.

"Taking this action would place a rejected nominee in an appointed term to the NLRB, setting an unfortunate precedent for all future nominations and future administrations," they said.

President George W. Bush, during his eight years in office, made a number of recess appointments, including many to the NLRB.

Update, 1:18 p.m.:  Kimberly Freeman Brown, the executive director of American Rights at Work, released the following statement:

“It is unconscionable for 41 Senators to hold the rights of workers hostage in the worst economy since the Great Depression. As we heard at the Supreme Court this week, even Chief Justice John Roberts recognizes that the recess appointment process is available to fill vacancies on the NLRB.  Workers need a fully functioning NLRB to mediate their claims for fair wages, benefits and other rights, but rather than defending workers rights today Republican Senators are making the lives of working people even harder.”