Democratic lawmakers are trying to increase pressure on National Labor Relations Board member William Emanuel to answer questions about why he didn't recuse himself from a major case.

The lawmakers obtained a delay in the vote for John Ring, President Trump's nominee to fill the last open seat on the NLRB, preventing the labor enforcement agency from getting a Republican majority.

A Democratic source on the Senate Health, Education, Labor and Pensions Committee who requested anonymity said the lawmakers didn't have an issue with allowing a hearing on Ring's nomination. "There is nothing like that. It's about concerns regarding the current board members and how they are doing their jobs," the source said.

Ring, a former member of management-side firm Morgan Lewis, was set to have his confirmation hearing before the committee Wednesday, but Chairman Lamar Alexander, R-Tenn., agreed to delay it at the request of Sen. Patty Murray of Washington, the committee's top Democrat, as a "courtesy," a Republican committee source who requested anonymity said. The hearing has been rescheduled to March 1, with a vote on his nomination set for March 7, said spokesman Taylor Haulsee.

The Democratic source said Alexander could have ignored their requests and gone ahead with the hearing but agreed to the delay to mollify Democrats' concerns. The delay will ensure that board retains its current split between two Republicans and two Democrats for now.

Emanuel, another Trump appointee and a former private-sector lawyer, provided a key vote in a case late last year called Hy-Brand Industrial Contractors Ltd. that overturned the Obama-era board's controversial "joint employer" policy. Democrats argue Emanuel should have recused himself because his former law firm represented one of the clients in the case that was overturned, called Browning-Ferris.

Joint employer refers to when one business is so intertwined with a second one that it can be held legally responsible the second business's workplace policies. Until 2015, that required "direct control" of the policies. But with Browning-Ferris, the NLRB changed it to the much vaguer "indirect control," which vastly expanded legal liability for corporations, especially franchisers. The Hy-Brand case restored the standard to "direct control."

Business groups praised the board's decision, arguing that the Obama board's policy was a vast overreach that would force companies out of the business of franchising. Union groups slammed the change as a sop to business groups.

The Democrats wrote Emanuel in late January to ask whether he had participated in the Hy-Brand vote. In a written response, Emanuel confirmed that he had and argued he was no obligated to recuse himself because the connection to his former law firm, Littler Mendelson, was too remote to merit that. However in a follow-up letter Feb. 1, Emanuel said he would update his response because "they require further clarification." The Democrats are still awaiting a response, the committee source said.

Trey Kovacs, labor policy expert at the libertarian Competitive Enterprise Institute, said the Democrats were being hypocritical. "Just a few short years ago, Democrats pleaded with Republicans to not block the vote on President Obama’s National Labor Relations Board nominees. They called on Republican senators to tone down the political rhetoric surrounding the agency, consider nominees on their merit, and consider the importance of the NLRB in protecting workplace rights. Now that the tables have turned, Democrats are obstructing a nominee's confirmation exclusively on political grounds," he said.