For what is Abraham Lincoln famously known?

Abraham Lincoln is famously known for the Emancipation Proclamation, which he issued on January 1, 1863. This pivotal document declared that all enslaved people in the Confederate states were to be set free, marking a crucial turning point in the American Civil War. Lincoln's proclamation not only aimed to undermine the Confederate war effort but also laid the groundwork for the eventual abolition of slavery throughout the United States with the passage of the Thirteenth Amendment. By issuing this executive order, Lincoln positioned himself as a key figure in the fight for civil rights and equality, cementing his legacy as a leader committed to the principles of liberty and justice.

While the other options are significant in American history, they do not specifically represent Lincoln's most renowned contributions. The Louisiana Purchase was an important expansion deal made by Thomas Jefferson, the Gettysburg Address, although a profound speech delivered by Lincoln at the cemetery's dedication, is somewhat secondary to the immediate impact of the Emancipation Proclamation on civil rights. The United States Constitution is the foundational legal document governing the nation, but it predates Lincoln and does not pertain directly to his specific legacy.