mostly from my own life experiences.
But I'm sure you already knew everything I stated.
As for Right to work - it was set in force by individual states but stems from the 1947 Taft-Hartley amendment to the National Labor Relations Act (1935) sanctioned a state's right to pass laws that prohibit unions from requiring a worker to pay dues, even when the worker is covered by a union-negotiated collective bargaining agreement.
I believe that Wikipedia or
http://www.nrtwc.org/
could help you with this one.