Democrat Mark Gaston Pearce has withdrawn his name from consideration for another term on the National Labor Relations Board.

“I will not be seeking another term at the NLRB,” the former labor board chairman told Bloomberg Law Feb. 5. “While I urge that the board return to five members so that it can continue to function with the appropriate quorum, I feel it’s best that I remove myself from the center of a political tug of war that has spanned five months.”

Pearce, a key ally of unions and the labor movement, served two terms on the board during a series of major pro-worker decisions during the Obama administration. The development spells another loss for unions under President Donald Trump’s administration. Republicans and business advocates strongly criticized Trump’s decision late last year to renominate Pearce. They’re pushing to keep the seat open, citing Republican vacancies during the Obama era.

The NLRB is tasked with enforcing the National Labor Relations Act and adjudicating workplace disputes between companies and unions, or individual workers.

Pearce was sworn in as a member in April 2010 and was confirmed to a second term in August 2013. That term expired in August 2018, after which came a somewhat surprising renomination by the Trump administration on Aug. 29. The renomination drew intense criticism from pro-business groups, who urged senators to reject one of the key officials behind the Obama-era NLRB’s pro-worker approach to workplace policies and regulations.

Lawmakers in Congress last year discussed a possible deal to move Pearce as part of a group of Trump nominees for leadership posts, but that never happened. Pearce’s nomination expired when the Senate failed to vote on it before the end of the year.

“I believe I’ve accomplished a lot while I was there,” Pearce told Bloomberg Law. “While I was willing to continue, I know there’s much good I can do outside the agency to protect its purpose and mission.”

The NLRB now has a 3-1 Republican majority, with one Democrat seat unfilled. The board is moving to reverse a wide range of policies from the Obama administration.

Pearce will begin teaching courses at Cornell University’s School of Industrial and Labor Relations in March.

“It’s my hope the agency will continue to embrace its mission as the statute was drafted,” he said.

The NLRB didn’t immediately respond to a request for comment.