The correct answer is had been drafted.
By the end of 1965, most American soldiers in Vietnam had been drafted.
In March 1965, President Lyndon B. Jhonson made the decision of sending United States troops to Vietnam. My the month of June, almost 82,000 soldiers were already in South Vietnam, ready to take action in the war. At first, the American people supported the decision but later, when society saw what was happening to these young men in the battlefront, protests increased against the United States participation in a war that the U.S. considered it was not theirs.