What was one significant action taken by Abraham Lincoln?

Abraham Lincoln's issuance of the Emancipation Proclamation in 1863 was a pivotal moment in American history. This executive order declared that all enslaved people in the Confederate states were to be freed, changing the character of the Civil War from a battle for the Union to a fight for freedom. The Proclamation not only aimed to weaken the Confederacy by depriving it of its labor force but also set the stage for the eventual abolition of slavery in the United States. This action is often regarded as a moral turning point for the nation, as it emphasized the values of liberty and equality.

Other options listed do not accurately reflect actions attributed to Lincoln. The Constitution was created long before Lincoln's presidency, in 1787. Disbanding the military contradicts Lincoln's leadership during the Civil War, as he actively worked to maintain and strengthen it to preserve the Union. Ending the Great Depression is associated with Franklin D. Roosevelt, who implemented measures in the 1930s to revive the economy, well after Lincoln's time.