The American Civil War (1861-1865) was major conflict between the seceded 11 states of the Confederacy and the 23 states of the Union. The Union was led by President Abraham Lincoln and  the Confederacy was led by President Jefferson Davis.             

There were several causes of the Civil War which included sectionalism, state's rights, and most importantly, slavery. The North was strongly opposed to slavery while the South depended on slavery for their agricultural production. The North had passed tariffs on foreign goods to keep the people from buying foreign goods and focused on the manufactured goods made by the North. This caused strong opposition from the South and led to the Nullification Crisis. The Nullification Crisis was ended by the Compromise Tariff that was proposed by Henry Clay that lowered the tariff when South Carolina threatened to secede from the Union. The North's economy was mainly based on manufactured goods and the South depended on farming and cash crops which led to the conflict over the tariffs. But on February 1861, seven states seceded from the Union and formed the Confederate States of America. Later on April through May of the same year, 4 more states seceded to join the Union. Then on April 12, 1861, Confederate troops attacked a federal military installation at Fort Sumter in South Carolina. The war had finally begun.

Abraham Lincoln (February 12, 1809 – April 15, 1865) was President of the United States from March 4, 1861 to April 15, 1865. As an outspoken opponent of the expansion of slavery and a political leader in the western states, he won the Republican Party nomination in 1860 and was elected president later that year. Lincoln helped preserve the United States by leading the defeat of the secessionist Confederacy in the American Civil War. He introduced measures that resulted in the abolition of slavery, issuing his Emancipation Proclamation in 1863 and promoting the passage of the Thirteenth Amendment to the Constitution in 1865.