Final answer:
Congress authorized retirement after 20 years of service with half pay for enlisted personnel in 1944 through the Servicemen's Readjustment Act, also known as the GI Bill of Rights.
Step-by-step explanation:
Congress authorized retirement benefits for enlisted personnel after 20 years of service with half pay in 1944 as part of the Servicemen's Readjustment Act, commonly known as the GI Bill of Rights. This legislation was born out of a concern for the well-being of soldiers returning from World War II and was part of a broader set of social changes recognizing the need for economic protections for aging workers. The Act played a crucial role in shaping the post-war social landscape, influencing not just military personnel but also the rise of social safety nets, including Social Security and later, Medicare. While the authorization for military retirement pay was a significant milestone, adjustments to civilian retirement provisions continued over the years, including incremental increases to the Social Security retirement age.