Final answer:
The main differences between the American troops stationed in Vietnam before and after 1965 include the increase in troop numbers, changes in tactics, longer deployments, and a shift in public support.
Step-by-step explanation:
The main difference between the American troops stationed in Vietnam before 1965 and those stationed there after that date is that the number of troops increased significantly after 1965. Before 1965, there were fewer troops in Vietnam, but after that date, more than 200,000 U.S. military personnel were sent to South Vietnam.
Another difference was in the tactics used by the troops. Before 1965, the troops relied on the South Vietnamese army, which often had little faith in their own government and struggled to effectively confront the Vietcong. After 1965, the U.S. troops took on a more active role in the war and implemented new tactics.
Regarding the duration of deployment, there was a change after 1965. The U.S. government committed close to 500,000 troops to the conflict in Vietnam, resulting in longer deployments for many soldiers.
The level of support from the American public also changed after 1965. At first, the American public supported the president's actions in Vietnam, but as more troops were deployed and casualties increased, support began to decline and antiwar protests emerged.