What was the immediate effect of the Confederacy firing on Fort Sumter?

The immediate effect of the Confederacy firing on Fort Sumter on April 12, 1861, was the outbreak of the Civil War. The attack galvanized Northern public opinion, leading to widespread support for the Union cause and a call for volunteers to suppress the rebellion. Additionally, it prompted President Abraham Lincoln to issue a call for 75,000 troops, marking a significant escalation in tensions between the North and South. The attack also solidified Southern states' resolve to secede and form the Confederate States of America.