WASHINGTON (AP) - Senate Democrats on Tuesday failed to push through President Barack Obama's choice of a union lawyer to serve on the National Labor Relations Board after two of their own joined Republicans to block the nomination.

By a 52-33 vote, Democrats fell far short of the 60 needed to overcome a GOP filibuster of the nomination of Craig Becker.

The vote is a setback for organized labor, which was counting on a strong pro-union voice on the agency that oversees union elections and referees labor-management disputes.

It's also a blow to the NLRB, which has postponed hundreds of cases for more than two years while political wrangling has stalled nominations to fill three vacancies on the five-member board.

Republicans have held up Becker's confirmation for months, saying they fear he would circumvent Congress to make labor laws more union-friendly.

But the task for Democratic leaders turned more difficult when two Democrats - Sen. Ben Nelson, of Nebraska, and Sen. Blanche Lincoln, of Arkansas - joined Republicans in opposing Becker. Both have come under intense pressure from the U.S. Chamber of Commerce and other business groups to oppose the nominee.

"Mr. Becker's previous statements strongly indicate that he would take an aggressive personal agenda to the NLRB, and that he would pursue a personal agenda there, rather than that of the administration," Nelson said in a statement.

Democrats had tried to push Becker through before Republican Scott Brown of Massachusetts came into office and took away Democrats' 60 vote supermajority. Brown voted against Becker.

Becker, a lawyer for the AFL-CIO and the Service Employees International Union, has spoken favorably on "card check" legislation that would take away the right of employers to demand secret ballot union representation elections. Some of his legal writings suggest that its goals could be accomplished by the NLRB without Congress having to pass the legislation.