Wagner Act of 1935?  Or the Taft-Hartley Labor Act of 1947, which amended the Wagner Act?  Or the Taft-Hartley Labor Act amendments of 1975?  Doesn't matter!

Reagan used it to allow companies to break laws during strikes, dishonored agreements, prolonged and/or prohibited strikes by his declarations.  Union protections and wages haven't been the same since.  The workers -- literally -- bargained away their rights out of desperation.

Whilst that was happening.  Lots of scabs (non-union scabs) were brought in to work for various companies, factories, mills, etc.  Most of the product produced by scabs -- was junk that could not be sold -- poor quality.  But the companies were willing to wait.

Companies spent millions and millions of dollars during that period of time.  The end goal was to reduce wages, and eliminate as many benefits as possible.  It worked.  Oh, and then start shipping our jobs, and their profits, out of the country.