A closed shop is a business or industrial establishment whose employees are required to be union members of the industry union as a precondition to employment.

This type of employment practice is now considered to be illegal in most, if not all, of the United States. Politicians of the New Deal era were often in favor, but the use of a closed shop was banned by the Taft-Hartley Labor Act of 1947, only to be amended 4 years later to allow it in certain circumstances.

Proponents of a closed shop hold that it will increase worker solidarity and union strength. The idea was popular amongst early trade unionist and was occasionally the impetus for strikes in the 19th and early 20th centuries. Business leaders have generally been opposed to the closed shop, although some people argue that the closed shop can be detrimental to new employees if the fees for union membership are too high.

Further reading

• Johnsen, J. E. The Closed Shop. 1942.