<P> While not all Southerners saw themselves as fighting to preserve slavery, most of the officers and over a third of the rank and file in Lee's army had close family ties to slavery . To Northerners, in contrast, the motivation was primarily to preserve the Union, not to abolish slavery . Abraham Lincoln consistently made preserving the Union the central goal of the war, though he increasingly saw slavery as a crucial issue and made ending it an additional goal . Lincoln's decision to issue the Emancipation Proclamation angered both Peace Democrats ("Copperheads") and War Democrats, but energized most Republicans . By warning that free blacks would flood the North, Democrats made gains in the 1862 elections, but they did not gain control of Congress . The Republicans' counterargument that slavery was the mainstay of the enemy steadily gained support, with the Democrats losing decisively in the 1863 elections in the northern state of Ohio when they tried to resurrect anti-black sentiment . </P> <P> The Emancipation Proclamation enabled African - Americans, both free blacks and escaped slaves, to join the Union Army . About 190,000 volunteered, further enhancing the numerical advantage the Union armies enjoyed over the Confederates, who did not dare emulate the equivalent manpower source for fear of fundamentally undermining the legitimacy of slavery . </P> <P> During the Civil War, sentiment concerning slaves, enslavement and emancipation in the United States was divided . In 1861, Lincoln worried that premature attempts at emancipation would mean the loss of the border states, and that "to lose Kentucky is nearly the same as to lose the whole game ." Copperheads and some War Democrats opposed emancipation, although the latter eventually accepted it as part of total war needed to save the Union . </P> <P> At first, Lincoln reversed attempts at emancipation by Secretary of War Simon Cameron and Generals John C. Frémont (in Missouri) and David Hunter (in South Carolina, Georgia and Florida) to keep the loyalty of the border states and the War Democrats . Lincoln warned the border states that a more radical type of emancipation would happen if his gradual plan based on compensated emancipation and voluntary colonization was rejected . But only the District of Columbia accepted Lincoln's gradual plan, which was enacted by Congress . When Lincoln told his cabinet about his proposed emancipation proclamation, Seward advised Lincoln to wait for a victory before issuing it, as to do otherwise would seem like "our last shriek on the retreat". Lincoln laid the groundwork for public support in an open letter published in abolitionist Horace Greeley's newspaper . </P>

Who caused the civil war north or south