The rights of the people are not limited to those specifically listed in the Constitution. People have other rights that aren’t listed, and those rights should be protected as well.
Before the Bill of Rights was added to the Constitution, Anti-Federalists were concerned that there wasn’t a comprehensive or complete list of individual rights in the Constitution. They also feared that listing certain rights might be interpreted to mean that only those rights were protected. The Ninth Amendment was added to clarify that the absence of a right did not mean that citizens could not claim that right.
