The NLRB's general counsel, Richard Griffin, said he intended to follow up on complaints by franchisee employees about their working conditions and to see whether the parent company was culpable.

In December, Griffin filed 19 complaints against franchisees, focusing on what he said were punitive actions taken against employees who supported union representation. The complaints allege that McDonald's Corp. itself is directing the anti-union campaign and therefore is no longer subject to protection by the franchisor-franchisee relationship. 

Labor lawyers told The Hill that because they believe the parent company is orchestrating the anti-union campaign, McDonald's must be the focus of any remedial action.

McDonald's has steadfastly insisted it is protected by the traditional arms-length relationship between itself and its franchisees. 

Griffin filed cases in major metropolitan areas around the U.S. The first are being considered at the regional level by administrative judges beginning this week. Next steps would be hearings before the five-person NLRB and then on to the federal courts.

Should Griffin's legal assault on the joint employer prevail, it could have ramifications for all franchise operators, Michael Lotito, an employment and labor attorney and co-chairman of Littler Mendelson's conservative Workplace Policy Institute, told The Hill.

"I think all businesses should recognize this is bigger than a McDonald's problem," he said.

While the McDonald's joint employer challenge has been high profile, a second, Browing-Ferris, could lead to even more sweeping changes in the relationships and responsibilities between companies and franchisees, vendors and subcontractor, The Hill reported.

The NLRB is currently weighing that case.

Griffin was a compromise NLRB general counsel appointee who narrowly won Senate approval after Obama's original choice, Lafe Solomon, was withdrawn due to ongoing controversy. He immediately raised Republican and employer hackles with his aggressive pursuit of what was termed a pro-union agenda.

Griffin's name had been floated prior to Solomon's but had met with resistance. With Obama pushing hard for him the second time around, the nomination prevailed. Griffin's term runs through 2017, meaning his influence could well survive a change in party leadership in the White House.