What's the Impact of Unions on the Working Class Agenda?

The number of workers who have unions in their work place has declined significantly over the past forty years. A lot of the things at simir just mentioned were won in an environment where unions had a lot more power than they do to day. Why have unions declined and how does that impact our ability to win a working class agenda to day? I think one thing that maybe people don't quite realizes how much the labor movement has declined over the last few decades.