Final answer:
The Emancipation Proclamation, issued by Abraham Lincoln on January 1, 1863, aimed to free slaves in Confederate territories as a military strategy during the Civil War. While it did not immediately free all slaves, it did mark a significant shift in the Union's war aims towards the abolition of slavery and altered the course of American history concerning civil rights.
Step-by-step explanation:
President Abraham Lincoln issued the Emancipation Proclamation on January 1, 1863, declaring that all slaves in Confederate territory would be 'thenceforward, and forever free.' However, the proclamation did not immediately free all enslaved people, particularly in areas without a Union army presence or in Border States which were not in rebellion. Lincoln justified the proclamation under his powers as commander-in-chief, as a military necessity during the Civil War. He was strategic in its issuance, having waited for a sign of Union strength at the Battle of Antietam. The historic proclamation also set the stage for future abolition of slavery by promoting the idea of compensated emancipation and voluntary colonization, though immediately it freed slaves mainly in areas of active rebellion.
While Lincoln aimed to preserve the Union at all costs, he increasingly saw abolition as strategically necessary. By depleting the Confederate states of their labor force, he struck at the rebellion’s capacity for war. Despite legal and political risks, Lincoln managed to use the proclamation in a way that avoided immediate legal challenges. The dramatic step not only reframed the Civil War as a struggle against slavery but also changed the national discussion on human rights, paving the way for eventual universal abolition.