Congress enacted the National Labor Relations Act (NLRA) in 1935 to protect the rights of employees and employers, to encourage collective bargaining, and to curtail certain private sector labor and management practices, which can harm the general welfare of workers, businesses and the U.S. economy.ec. 303. [§ 187.] (a) It shall be unlawful, for the purpose of this section only, in an industry or activity affecting commerce, for any labor organization to engage in any activity or conduct defined as an unfair labor practice in section 8(b)(4) of the National Labor Relations Act [section 158(b)(4) of this title].