The Emancipation Proclamation:

The Emancipation Proclamation, issued by President Abraham Lincoln on January 1, 1863, was a pivotal moment in American history, marking a significant shift in the purpose of the Civil War. The proclamation declared that all slaves in areas still in rebellion against the Union were free, effective immediately, citing the war powers granted to the President by the Constitution. While it did not immediately free all slaves, as it did not apply to border states or areas already under Union control, it sent a powerful message about the federal government's commitment to ending slavery. The Emancipation Proclamation also had a profound impact on the war effort, as it allowed African American men to enlist in the Union army and served as a rallying cry for abolitionists and those fighting for freedom. In the years that followed, the proclamation paved the way for the eventual passage of the 13th Amendment to the Constitution, which formally abolished slavery throughout the United States.