Final answer:
The American Civil War officially began with the Confederate attack on Fort Sumter in Charleston, South Carolina, on April 12, 1861, following heightened tensions after Lincoln's election and the secession of several Southern states.
Step-by-step explanation:
The official starting point of the American Civil War is widely recognized to be the Confederate attack on Fort Sumter in Charleston, South Carolina, on April 12, 1861. This attack ignited the Civil War following a period of intense sectional tension after Abraham Lincoln's election in 1860. The firing upon Fort Sumter, a Union garrison, by Confederate forces marked the beginning of hostilities between the North and the South. With the fall of Fort Sumter, President Lincoln called for seventy-five thousand volunteers to join federal forces, expecting a swift ninety-day campaign to suppress the Southern rebellion, which instead escalated into a prolonged and brutal war.
Days after the attack, President Lincoln issued a call for troops to quell the rebellion, a move that signaled the full scale of mobilization for the war effort. Following these events, several other states faced the decision of whether to secede and join the Confederacy or remain in the Union. This crucial period was the catalyst for four years of civil war that not only shaped the nation's future but also had profound implications for issues like slavery and states' rights.