Considered by many historians to be an "irrepressible conflict," the Civil War erupted as a result of a number of complex, divisive issues that had gone unresolved since the time of the "incomplete American Revolution of 1776." Prominent among the factors that shattered the nation were sharp political, social and economic differences between the northern and southern states, the most pressing of which was the expansion of slavery into the western territories.

Abraham Lincoln was elected to the presidency in 1860 with no support in the South. Lincoln and his administration had promised to work to harness federal power to prohibit the expansion of slavery as well as promoting the free-labor economy of the North "through protective tariffs, subsidies for railroads and free homesteads in the West."

Many southerners saw in the Republican platform a direct threat to their cherished way of life. Within weeks of the election, but long before the Republican administration took office, seven southern states seceded from the Union. In April 1861, Lincoln ordered an expedition to relieve the federal garrison at Fort Sumpter, South Carolina, at which point Confederate authorities ordered an attack on the fort.

When Lincoln called for 75,000 state militia to put down the "insurrection, "" four more states seceded. These were the opening moves in a war that would claim more than 600,000 American lives before it ended in the spring of 1865--a war in which "brother fought brother" until the bitter end. With the sectional conflict finally settled, "the United States was free to complete the task of conquering the continent and move toward realizing its destiny as one of the great nations of the world."

Union Casualties in the Civil War 1861 - 1865

Branch of Service	Number Serving	Killed in Action	Other Deaths	Non-mortal Wounds
Army	2,128,948	138,514	221,374	280,040
Navy		2,112	2,411	1,710
Marines	84,415	148	312	131
Total	2,213,363	140,414	224,097	281,881