Final answer:
Forrest Gump served in the U.S. Army during the Vietnam War, a conflict that shaped U.S. military tactics and strategies.
Step-by-step explanation:
Forrest Gump, the fictional character from the eponymous film, served in the U.S. Army during the Vietnam War. This major conflict occurred from the 1950s to the 1975, involving intense combat and significant U.S. military deployment, where troops experienced challenging conditions and complex relations with the local terrain and politics. The conflicted period in Vietnam highlights several critical aspects of U.S. military history, including tactical innovations such as the Ranger Companies and strategic transitions influencing how wars were fought, taking lessons learned from previous conflicts like World War II and the Korean War.