Final answer:
The Thirteenth Amendment, passed by Congress in January 1865 and ratified in December 1865, abolished the institution of slavery in the United States. This action followed efforts by individual states and legislative moves during the Civil War that limited or outlawed slavery, culminating in the formal emancipation of four million people.
Step-by-step explanation:
The Abolition of Slavery in the United States
The institution of slavery in the United States was officially abolished by the Thirteenth Amendment, which was passed by Congress on January 31, 1865, and later ratified by the necessary three-fourths of the states. This pivotal Amendment came after President Lincoln's Emancipation Proclamation, which had declared the freedom of enslaved people in the rebellious states during the Civil War. The full abolition of slavery represented the culmination of a long-standing effort by abolitionists who argued that slavery was contrary to the ideals of the Declaration of Independence, Christian teachings, and fears about public safety and the growing dependence on enslaved labor. After the Civil War, the Amendment ensured that neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, bringing an end to a practice that had persisted for 250 years.
Prior to the Thirteenth Amendment, individual states took measures to restrict or end slavery. Pennsylvania passed the Act for the Gradual Abolition of Slavery in 1780 and Massachusetts freed all enslaved people within the state in 1783. Throughout the United States, many Americans saw slavery as inconsistent with the country's values and moved toward its termination. The Republican-dominated Congress took decisive steps during the Civil War, including passing the Confiscation Acts and abolishing slavery in Washington, DC, and in the territories. These efforts laid the groundwork for the eventual passage of the Thirteenth Amendment, which was ratified in December 1865, ensuring that four million people were forever free from the bonds of slavery.