President Abraham Lincoln (1809–1865) issued the Emancipation Proclamation (the document that declared slaves to be free) after the Civil War (1861–65) had been raging for a year. He delayed because, in spite of growing pressure from abolitionists (those who wanted to outlaw slavery), slavery had not been the main issue in the war between the Confederacy (states in the South) and the Union (states in the North; the United States). Instead, the primary reason for the war was the Southern states concern over their right to make their own laws and control their economies. Southern leaders consequently feared that their agricultural economy, which was based on slave labor, was being threatened by the industrialized North, which was based on paid labor. In addition, the war had not been going well for the Union, and Lincoln knew he had no real power to free slaves in the South. In the summer of 1862 Union troops were defeated again, at the Second Battle of Bull Run, which took place in northeastern Virginia on August 29 and 30. But on September 17, at the Battle of Antietam in Maryland, the Union finally forced the Confederates to withdraw across the Potomac River into Virginia. That was the bloodiest day in the war so far. Lincoln decided that the Confederate withdrawal was success enough for him to make his proclamation, and on September 22, he called a cabinet (adviser) meeting. That day he presented to his advisers the Preliminary Emancipation Proclamation.
The official Emancipation Proclamation was issued later, on January 1, 1863. This final version differed from the preliminary one in that it specified emancipation was to be effected only in those states that were in rebellion (that is, the South). This key change had been made because the president's proclamation was based on congressional acts giving him authority to confiscate Confederate property (meaning slaves) and forbidding the military from returning slaves of Confederates to their owners, thus limiting the rights of these states. Abolitionists in the North, however, criticized the president for limiting the scope of the Proclamation to the Southern states, for it left open the question of how slaves and slave owners in Northern states should be dealt with.
On January 31, 1865, just over two years after the Emancipation Proclamation was issued, Congress passed the Thirteenth Amendment to the U.S. Constitution (the document that states the nation's laws), banning slavery throughout the United States. Lincoln, who had lobbied (influenced public officials) hard for this amendment, was pleased with its passage. The Confederate states, however, did not free their 4,000,000 slaves until after the Union defeated them in the war on April 9, 1865.
Further Information: Emancipation Proclamation. [Online] Available http://www.tbwt.com/interaction/lincoln/html/1.htm, November 1, 2000; Emancipation Proclamation. [Online] Available http://rs6.loc.gov/ammem/alhtml/almtime.html, November 1, 2000; Thomas, Benjamin P. Abraham Lincoln: A Biography. New York: Barnes & Noble Books, 1993.