During which historical period did labor unions receive notable legal protections in the U.S.?

Labor unions gained significant legal protections during the Great Depression era, primarily due to the economic hardships faced by workers and the need for organized labor to advocate for better working conditions, wages, and job security. The passage of the National Labor Relations Act (Wagner Act) in 1935 was a pivotal moment that established workers' rights to organize and engage in collective bargaining. This legislation created mechanisms for workers to form unions and prohibited unfair labor practices by employers, solidifying the position of labor unions within the American economic framework.

During this period, the federal government recognized the importance of labor organizations in addressing the widespread unemployment and unfair labor conditions present during the Great Depression, which led to a more favorable legal environment for unions. In contrast, the other historical periods mentioned did not see similar advancements in labor rights and protections, as the focus and social climate differed significantly in those eras.