Effect of the Emancipation Proclamation

During the American Civil War, President Abraham Lincoln issued a significant executive order known as the Emancipation Proclamation. This proclamation declared the freedom of all enslaved people in the states that were in rebellion against the Union, aimed at weakening the Confederacy while also laying the groundwork for the eventual abolition of slavery in the United States. To better understand the implications of this historic document, what was one major effect of the Emancipation Proclamation?