What did the Emancipation Proclamation achieve?

The Emancipation Proclamation achieved the significant milestone of declaring all enslaved individuals in Confederate states to be free. Issued by President Abraham Lincoln on January 1, 1863, this executive order aimed to weaken the Confederacy's war effort by undermining its labor force, as slaves were integral to the Southern economy and military.

While it did not immediately free all enslaved people, as it applied only to territories in rebellion against the Union and did not affect slave-holding border states loyal to the Union, it fundamentally shifted the purpose of the Civil War towards a fight against slavery. The proclamation allowed for the enlistment of African American soldiers into the Union Army, further contributing to the Union’s strengths. This measure not only redefined the war but also set the stage for the eventual passage of the Thirteenth Amendment, which abolished slavery throughout the United States.

In contrast, the other options address unrelated historical events or concepts. The Mexican-American War concluded before the Emancipation Proclamation, the League of Nations was established after World War I, and the proclamation did not seek to limit the federal government's power but rather expanded it by asserting the government's authority to take action against slavery during wartime.