Which historical document or event formally abolished slavery in the United States, effectively ending slave auctions?

The Emancipation Proclamation is the historical document that formally abolished slavery in the United States, marking a significant turning point in the nation’s history. Issued by President Abraham Lincoln on January 1, 1863, the proclamation declared that all enslaved people in the Confederate states were to be freed. This act not only aimed to inspire enslaved individuals to escape to freedom but also sought to undermine the Confederacy's ability to sustain its war efforts.

The significance of the Emancipation Proclamation goes beyond its immediate legal implications. It redefined the Civil War's purpose, framing the conflict as a struggle for freedom and human rights, and paving the way for the eventual passage of the Thirteenth Amendment in 1865, which abolished slavery throughout the entire country.

In contrast, the other choices do not serve the same function regarding the abolishment of slavery. The Missouri Compromise was primarily about the balance between free and slave states rather than the abolition of slavery itself. The Declaration of Independence, while foundational in establishing the principles of liberty and equality, did not address slavery directly or lead to its abolition. The Underground Railroad, though significant in assisting enslaved individuals to escape to freedom, was a network rather than a formal policy