LAS VEGAS - Three Democratic presidential hopefuls tried to show off their union bona fides Friday at a rally of cocktail waitresses, housekeepers and line cooks who make up the state's largest labor union.
"We're not going to let the Republicans in Washington or anywhere else treat working families as if they were invisible," New York Sen. Hillary Rodham Clinton told the crowd. "You're not invisible to us, you are not invisible to this union and you're sure not invisible to me."
Clinton spoke to thousands of members of the Culinary Workers Union, Local 226, a group expected to be a key organizing force in Nevada's new early caucus.
Illinois Sen. Barack Obama and …