UNDATED (AP) -- As the nation celebrates Labor Day, supporters of labor unions say they are continuing to lose ground.
Paul Clark, head of Penn State's Department of Labor Studies, says there's been what he calls a "concerted attack" on unions for several decades by employers and from the political right, and he says it's been "very effective."
Clark says unions represented about 35 percent of workers in the last century, but now represent only 7 or 8 percent of the private sector work force. He says that's diminished not only their impact in the workplace but also their political influence.
AFL-CIO executive VP Arlene Holtbaker says she's optimistic that that will change -- though she says it will be "challenging" because labor laws have been weakened.