In 1935, when Congress passed the National Labor Relations Act (also known as the NLRA, or the Wagner Act), it recognized the direct relationship between the inequality of bargaining power of workers and corporations and the recurrent business depressions. That is, by depressing wage rates and the purchasing power of wage earners, the economy fell into depression. The law therefore recognized as policy of the United States the encouragement of collective bargaining.

Michael Barnes – http://www.examiner.com/conservative-in-chicago/judge-re-mcpier-no-interference-collective-bargaining