The Senate on Wednesday morning moved forward on President Trump's pick of Marvin Kaplan to fill an open seat on the National Labor Relations Board, the main federal labor law enforcement agency.

Democrats and organized labor groups oppose the pick, who with Trump's choice for the NLRB's other open seat, William Emanuel, would give the board a Republican-led majority. The 50-48 cloture vote sets up a final Senate vote on Kaplan by the end of the week.

Kaplan is chief counsel of the Occupational Safety and Health Review Commission, a federal agency. Prior to that he was a Republican staffer for the House Education and the Workforce Committee. Emanuel is a shareholder with Littler Mendelson, a management-side law firm that specializes in labor matters, often before the NLRB.

Should they be confirmed, they would give the board a Republican majority for the first time since President George W. Bush's administration. The NLRB's members are nominated by the president but the agency otherwise operates independently. It currently has a Republican chairman, Philip Miscimarra, but the other two members, Mark Gaston Pearce and Lauren McFerran, are Democratic nominees and the board operates by simple majority.

Liberal groups argue that Kaplan in his career has shown hostility to the board's mission of enforcing the National Labor Relations Act. They also noted that, unlike Emanuel, Kaplan has no actual background in labor law litigation.

"The board members should be committted to the board's core mission," said Sen. Patty Murray, D-Wash. "As a House staffer he organized and prepared hearings where Republicans attacked the NLRB ... I have also have deep concerns about his lack of experience."