In the middle of the nineteenth century, the United States embarked on a new relationship with death, entering into a civil war that proved bloodier than any other conflict in American history, a war that would presage the slaughter of World War I’s Western Front and the global carnage of the twentieth century. The number of soldiers who died between 1861 and 1865, an estimated 620,000, is approximately equal to the total American fatalities in the Revolution, the War of 1812, the Mexican War, the Spanish-American War, World War I, World War II, and the Korean War combined. The Civil War’s rate of death, its incidence in comparison with the size of the American population, was six times that of World War II. A similar rate, about 2 percent, in the United States today would mean six million fatalities. As the new southern nation struggled for survival against a wealthier and more populous enemy, its death toll reflected the disproportionate strains on its human capital. Confederate men died at a rate three times that of their Yankee counterparts; one in five white southern men of military age did not survive the Civil War.
Above from This Republic of Suffering by Drew Gilpin Faust, a new history of the reaction to the unprecedented death and dying of the American War of the Rebellion.