The Fourteenth Amendment has had the greatest impact on increasing civil rights. This amendment, ratified in 1868, granted citizenship to all persons born or naturalized in the United States, including former slaves, and guaranteed equal protection under the law. It greatly expanded the civil rights of individuals, ensuring that states could not infringe upon basic rights and liberties. The Fourteenth Amendment has been used as the legal basis for many landmark civil rights rulings, including Brown v. Board of Education, which desegregated schools, and Obergefell v. Hodges, which legalized same-sex marriage.
