Attorneys representing federal employee unions and the White House this month debated an whether an untested theory of federal sector labor law enabled labor groups ousted due to President Trump’s executive orders stripping two-thirds of the federal workforce of their collective bargaining rights administratively, a question that could upend the fight over federal employees’ rights.

At issue is a provision of the 1978 Civil Service Reform Act that allows federal workers to petition the Federal Labor Relations Authority over the makeup of a bargaining unit or whether a union enjoys majority support from the workforce it represents.

Though it has traditionally been used only to resolve disputes over whom to include or exclude from a bargaining unit, attorneys with the Justice Department have argued that the phrase “or a matter relating to representation” grants unions a lane to challenge their exclusion from the federal workplace as a result of Trump’s executive orders, signed last March and August, seeking to decertify unions at most federal agencies on national security grounds.