Which amendment abolished slavery in the United States?

The 13th Amendment is significant because it formally abolished slavery in the United States. Ratified in December 1865, the amendment states that neither slavery nor involuntary servitude, except as punishment for a crime, shall exist within the United States or any place subject to their jurisdiction. This was a monumental change in American law and society, marking a key turning point in the nation's history, especially following the Civil War.

The other amendments mentioned serve different purposes. The 12th Amendment details the procedure for electing the President and Vice President, the 14th Amendment addresses citizenship rights and equal protection under the law, and the 15th Amendment prohibits the denial of the right to vote based on race, color, or previous condition of servitude. Each has its own importance in shaping civil rights and governance, but none of these amendments abolished slavery, which makes the 13th Amendment the correct answer.