Final answer:
An individual who has served and left the U.S. armed forces with an honorable discharge is termed as a 'veteran.' Not all discharge types were equal, as exemplified by blue discharges and later, undesirable discharges, both of which impacted gay and lesbian service members' eligibility for benefits.
Step-by-step explanation:
An individual who has served in the armed forces of the United States, particularly during a time of war, and has left the service with an honorable discharge is best described as a veteran. This person has fulfilled their duty to their country and is no longer actively serving. Veterans often are eligible for certain benefits, including healthcare and education, through the Veterans Administration (VA). However, not all discharges from service are considered equal. From World War II until 1947, the VA used blue discharges, which were neither honorable nor dishonorable, but they did disqualify service members from benefits and often led to discrimination. After 1947, the blue discharge was replaced by an undesirable discharge category, continuing discrimination against gay and lesbian service members, among others.
During the post-war era, policies and attitudes within the military regarding sexual orientation led to the expulsion of many gay and lesbian members. After the Korean War, the crackdown on gay and lesbian service members resumed, with many being expelled under an undesirable discharge, removing their eligibility for veteran benefits. Moreover, the rights and treatment of conscientious objectors, those unwilling to serve based on moral, ethical, or religious beliefs, have also been an area of contention within the armed services history.