Answer: The Ninth (9th) Amendment
Explanation: The federalists needed to ensure that the Constitution wouldn’t be misconstrued or be thought that the rights written in the document are the only rights Americans have. To resolve this problem, they added the ninth amendment, which states, “The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people.” This means that just because certain rights may not be included in the Constitution / Bill of Rights, that does not mean that they are not guaranteed rights. Of course, the Constitution’s wording and rights are still disputed to this day and both sides argue whether or not something is a right or not all the time, but because of the Ninth Amendment, at least things like the Right to Travel, Right to Vote (For White Males at that time but later every of age citizen), Right to Privacy, and other fundamental freedoms that are not explicitly or clearly stated in the Constitution. It’s very difficult to fit everything into one document, so that’s why they made sure to be safe and include that amendment. Like said, the amendment has led to speculation about the validity or truthfulness of a “Constitutional Right” and debate about if it is one, so that’s a bad side of it, but overall it did help people better understand civil liberties at the time and for generations to come.