Who played a significant role in abolishing slavery in the U.S.?

Abraham Lincoln played a significant role in abolishing slavery in the United States primarily through his leadership during the Civil War and his issuance of the Emancipation Proclamation in 1863. This landmark executive order declared the freedom of all enslaved people in states that were in rebellion against the Union, thereby shifting the war's focus to not only preserving the Union but also ending the institution of slavery. Lincoln's strong advocacy for the passage of the Thirteenth Amendment, which formally abolished slavery in 1865, further solidified his pivotal role in this transformative period of American history. His political actions and moral stance against slavery substantially contributed to the eventual end of slavery in the nation.