Final answer:
The Civil War is called the first Modern War due to its use of technologies such as railroads, steamboats, and the electric telegraph, marking a shift to more industrialized warfare. This conflict laid the foundational changes that would later be fully realized in World War I with its massive use of new warfare technology and tactics.
Step-by-step explanation:
The American Civil War is often referred to as the first Modern War because it incorporated technologies and strategies that represented a transition from traditional warfare to a more industrialized and technology-driven form of conflict. This war saw the significant use of railroads and steamboats for the rapid movement of troops and supplies, as well as the electric telegraph for improved communication. These advancements alongside industrial production capabilities, especially in the northern states, marked a clear departure from previous wars.
However, it's important to not confuse the Civil War with World War I, which further expanded the concept of modern warfare. World War I included the introduction of tanks, airplanes, machine guns, and chemical weapons on an unprecedented scale, affecting both military personnel and civilians, and is recognized as a total war. The term modern war, with respect to the Civil War, relates to the beginnings of these technological and logistical changes, setting the stage for future conflicts like World War I.