Stephan Savoia, Associated Press
Republican presidential candidate former Massachusetts Gov. Mitt Romney, left, campaigns with former Sen. John McCain, R-Ariz., during a town hall style meeting in Manchester, N.H., Wednesday, Jan. 4, 2012. Romney accepted an endorsement from McCain, the 2008 Republican presidential nominee, as he pushed for an overwhelming victory in next week's New Hampshire primary.

COLUMBIA, S.C. — Republican presidential candidate Mitt Romney is bashing the National Labor Relations Board in a new South Carolina ad airing the day after the Obama administration announced recess appointments to the labor panel.

South Carolina Gov. Nikki Haley had challenged GOP presidential hopefuls to take positions on the NLRB's legal action threatening jobs at a Boeing Co. plant in North Charleston. The NLRB charged that the company was building the facility in South Carolina in retaliation over labor contract fights.

In the 30-second ad set to air Thursday, Romney appears to talk from the factory floor with wood and scaffolding in the background. The scene changes to an exterior shot of a Boeing Co. plant, a jet engine and the 787 Dreamliner that Boeing is building in South Carolina and Washington state.

Romney accuses President Barack Obama of adopting policies that "affect our economy based not upon what's right for the American worker but, instead, what's right for their politics." He goes on to contend that the board is stacked with "union stooges" and calls the board's action "simply un-American" and "political payback."

The Boeing issue was resolved last month when Boeing and the union reached a contract extension and the NLRB dropped its legal action.

On Wednesday, Obama made three recess appointments to fill the NLRB to five members. The recess appointments allow the agency to continue to operate and avoid intervention by GOP opponents who say the agency favors unions.

Sen. Lindsey Graham, R-S.C., urged Obama to withdraw the appointments and called on House and Senate committees to investigate contacts between the NLRB and Boeing's machinists union.