WASHINGTON (AP) — President Barack Obama's newest picks for the National Labor Relations Board sought to assure Senate lawmakers Tuesday that they can be fair and impartial in resolving business-labor disputes, despite backgrounds that include advocating for unions.

The comments came at a hearing for Nancy Schiffer, former associate general counsel to the AFL-CIO, and Kent Hirozawa, chief counsel to the NLRB's chairman. The two were nominated last week as part of a deal in which Republicans agreed to end delaying tactics that blocked some of Obama's appointments.

They would replace Richard Griffin and Sharon Block, who spent more than a year on the board as recess appointments. A fight over Obama's decision to make the recess appointments — bypassing the Senate — helped set off the Senate showdown earlier this month over filibusters. The NLRB recess appointments have been ruled invalid by three appeals courts and the Supreme Court has agreed to resolve the dispute.

The hearing was unusual in that Republicans knew whatever complaints they made about the nominees, their confirmation has already been deemed a virtual certainty. As part of their deal with Democrats, Republicans agreed to a lightning-quick confirmation process for Schiffer and Hirozawa. In exchange, Senate Majority Leader Harry Reid agreed not to trigger a change in Senate procedures to strip the minority party of its ability to delay votes.

A committee vote is set for Wednesday and the full Senate could vote on their nominations as early as next week.

At the hearing, Republicans refrained from open criticism and instead repeatedly sought assurances that the nominees would not favor union interests over those of the business community.

"What can you say to employers who will come before a board that might include you that you've moved from the position of advocate ... to an impartial judge?" asked Tennessee Sen. Lamar Alexander, top Republican on the Senate Health, Education, Labor and Pensions Committee.

"I appreciate that these are two different roles — advocate and neutral arbiter," Schiffer said. "I have no preconceived agenda."

Hirozawa insisted he has "a very clear understanding of the difference between someone who's an advocate and someone who is an impartial adjudicator."

But the business community has eyed the nominees warily. The labor board, which resolves disputes between businesses and organized labor, has been a politically charged battleground for years. Republicans assert the board under Obama has been a tool of organized labor, seeking to make rules that would help unions organize new members. Democrats contend that Republicans were trying to shut the board down to prevent it from protecting workers' rights.

Schiffer spent more than a decade as a top lawyer the AFL-CIO. She began her career working at the NLRB's Detroit regional office and later worked at the United Auto Workers union, where she became the union's deputy general counsel.

She is seen as an ardent supporter of union rights, having previously testified in Congress in favor of the Employee Free Choice Act, a measure that would make it easier for unions to organize workers.

Hirozawa started his legal career as a field attorney for the NLRB's Manhattan office before moving to private practice at a law firm that represents unions. He returned to the board three years ago to be chief counsel to Mark Pearce, the board's chairman.

Their promises of even-handedness did not seem to satisfy Sen. Orrin Hatch, R-Utah, who said other former union lawyers nominated to the board have made similar promises.

"I don't think those promises they made here were kept," Hatch said.

But Iowa Sen. Tom Harkin, top Democrat on the committee praised both candidates as exceptionally qualified.

"I hope that this agreement brings a new beginning for the board so that we can ratchet down the political rhetoric that seems to surround this agency and instead let the dedicated public servants who work there do their jobs," Harkin said.

Confirmation of the NLRB nominees would be the last piece in resolving the dispute over seven of Obama's stalled nominees. Last week, the Senate quickly confirmed other blocked nominees to head the Labor Department, Environmental Protection Agency, Consumer Financial Protection Bureau and Export-Import Bank.

Besides Schiffer and Hirozawa, the Senate is also expected to confirm Pearce to a new term as NLRB chairman. Two Republican nominees, lawyers Harry Johnson III and Philip Miscimarra, are also expected to be confirmed.

If all five of Obama's nominees win confirmation by the full Senate, it would be the first time in a decade that the board has five Senate-confirmed members.