Motivation Behind the Emancipation Proclamation

In January 1863, President Abraham Lincoln issued the Emancipation Proclamation, a landmark document that transformed the nature of the Civil War and the status of enslaved people in the United States. This executive order declared the freedom of all enslaved people in Confederate-held territory. However, it also had significant implications for the Union, the war efforts, and international perspectives on the conflict. What was one of the primary motivations behind Lincoln's decision to issue the Emancipation Proclamation?