Final answer:
Samuel Gompers referred to the Wagner Act as "labor's Magna Charta" because it significantly strengthened workers' rights to form unions and collectively bargain, leading to better wages and conditions.
Step-by-step explanation:
Samuel Gompers called the National Labor Relations Act, commonly known as the Wagner Act, "labor's Magna Charta". The Wagner Act was a pivotal piece of legislation enacted in 1935 that provided federal support for workers' rights to form unions and engage in collective bargaining. With Gompers at the helm of the American Federation of Labor (AFL), the Act played a crucial role in strengthening labor unions and enhancing workers' negotiating power, leading to improved wages and working conditions.