Final answer:
The claim that labor arbitration in the U.S. first occurred in 1865 and became popular before World War II is false; the significant rise in unionization happened in the 1930s following the NLRA of 1935.
Step-by-step explanation:
The statement that labor arbitration first occurred in the United States in 1865 and became popular before World War II is false. While trade and labor unions have been active since the latter part of the 19th century, the major rise in union membership and organized labor activities in the U.S. are more closely associated with the 1930s, particularly following the passage of the National Labor-Management Relations Act of 1935, also known as the National Labor Relations Act (NLRA). This law paved the way for a substantial increase in union membership by securing workers' rights to organize and to have their unions recognized by management. During World War II, union membership was further bolstered as the government recognized unions as vital to the war effort, only to be followed by a decline in the legal support with the Taft-Hartley Act of 1947, which allowed workers to opt out of unions. The decline in union membership in the United States has been attributed to several factors, including changes in the legal environment, structural changes in the economy, and the perception of unions' roles.