The key Reconstruction Amendments passed after the Civil War were the 13th, 14th, and 15th Amendments to the United States Constitution. These amendments were critical in shaping the post-Civil War era and aimed at addressing the issues of slavery and ensuring civil rights for the newly freed African Americans.

1. 13th Amendment (1865): This amendment abolished slavery and involuntary servitude, except as punishment for a crime. It was the first of the Reconstruction Amendments and officially ended the institution of slavery in the United States.

2. 14th Amendment (1868): This amendment granted citizenship to all persons born or naturalized in the United States, which included former slaves who had just been freed. It also provided all citizens with “equal protection under the laws,” significantly laying the groundwork for civil rights legislation.

3. 15th Amendment (1870): This amendment aimed to prohibit federal and state governments from denying a citizen the right to vote based on “race, color, or previous condition of servitude.” It was intended to enfranchise African American men, although its implementation was resisted in various states for many years.

These amendments were pivotal in the effort to rebuild and redefine the United States following the Civil War, particularly in terms of civil rights and liberties.