Sectional Tensions

The Civil War marked a defining moment in United States history. Long simmering sectional tensions reached a critical stage in 1860-1861 when eleven slaveholding states seceded and formed the Confederate States of America. Political disagreement gave way to war in April 1861, as Confederates insisted on their right to leave the Union and the loyal states refused to allow them to go. Four years of fighting claimed almost 1.5 million casualties directly affected untold civilians, and freed four million enslaved African Americans. The social and economic system based on chattel slavery that the seceding states had sought to protect lay in ruins. The inviolability of the Union, most of the loyal citizenry 's pre-eminent concern throughout the conflict,

Although Lincoln and the victorious Republicans had promised not to interfere with slavery in states where it already existed, they firmly opposed slavery 's spread to any federal territories. Between December 1860 and February 1861, the seven Deep South states seceded to avoid what they perceived as a long-term threat to their slaveholding interests. After Confederates fired on Fort Sumter in mid-April 1861, Lincoln 's call for 75,000 volunteers to suppress the rebellion prompted four slave states of the Upper South, including Virginia, to join their Deep South brethren. Four other slave states, typically called the Border States, remained loyal to the Union. The United States mustered at least 2.1 million men, about half of its 1860 military-age population. More than 180,000 African American men served in United States Army units and another 20,000 in the Navy. Apart from its much larger population, the United States held decided advantages in industrial capacity, commercial interests, and financial infrastructure. The United States sought to compel the seceded states to abandon their hopes to found a new nation. Military fortunes ebbed and flowed for more than three years before United States forces gained a decisive advantage. The loyal states wavered more than once in their determination, most notably after Robert E. Lee frustrated Union offensives in the spring of 1863 and the spring and early summer of 1864. By the autumn of 1864, with Grant as the Union general in chief, United States armies applied pressure in Virginia, Tennessee, and the Carolinas that eventually forced a Confederate surrender in the spring of 1865. In the United States, they labored as nurses, government clerks, factory workers, members of the United States Sanitary Commission and other charitable