During the Industrial Revolution, the growth of enormous industrial establishments with a correspondingly large number of workers hired to perform increasingly simple tasks manifested the inability of an individual effectively to bargain with an employer concerning wages, hours, and other terms and conditions of the employment relationship. The resulting discontent among workers produced long and bitter, often bloody, outbreaks of economic warfare between employers and employees. In the abstract, freedom of contract was possible still, but as a practical matter employment benefits and obligations were largely established by managerial fiat. It was felt that if employees could effectively unite for bargaining, their collective power might balance that of the employer, thereby vitalizing the abstraction. The enactment in 1935 of the National Labor Relations Act,' the Wagner Act, represented, in essence, an attempt to strike that balance so as to reduce or eliminate industrial strife in interstate commerce.
J. Gilmer Bowman, Jr.,
An Employer's Unilateral Action -- An Unfair Labor Practice?,
9 Vanderbilt Law Review
Available at: https://scholarship.law.vanderbilt.edu/vlr/vol9/iss3/3