Final answer:
Lincoln's assertion that the 'magnitude and duration' of the war surprised both sides is true. The American Civil War lasted longer than anticipated and had significant impacts on both the North and the South.
Step-by-step explanation:
Magnitude and Duration of the War
Lincoln's assertion that the 'magnitude and duration' of the war surprised both sides is
true
. At the beginning of the American Civil War, both Northerners and Southerners believed that the conflict would be resolved quickly. However, as the war continued, it became clear that there was no quick resolution in sight. The war lasted for four years, taking a toll on both the North and the South. The longer the war persisted, the more it affected the lives of people on both sides as they had to face increased need for manpower, the issue of slavery, and the ongoing challenges of sustaining the war effort.