[Excerpt] Since the NLRA was amended by the Taft-Hartley Act in 1947, individual states have had the option of enacting laws that prohibit union security agreements. These state laws supersede the union security provisions of the NLRA and are known as right to work (RTW) laws. As of this writing, 23 states have enacted RTW laws. This report is divided into two parts. The first part discusses RTW laws themselves. It provides a brief legislative history on the federal role in the regulation of unions, a summary of the origin and development of RTW laws, a discussion of recent events at the state level, and federal legislation related to RTW. The second part of the report reviews the varied empirical research on the effects of RTW laws. Specifically, it will discuss the mixed evidence indicating relationships between RTW laws and other economic outcomes.