The overall impact of the Taft-Hartley Act of 1947 was that it placed limits on unions.
The Taft-Hartley Act, or the Labor Management Relations Act, is the 1947 law that regulates the activities and power of trade unions in the United States.
This law imposed restrictions on the "union shop", which obliged non-union workers to join the union within a certain period of time, or lose their jobs. Restrictions were also provided for "closed shop", work contracts that obliged them to be part of the union to be hired. The obligation for union leaders to take the oath of extraneousness to communist doctrines was also introduced.