Many Antifederalists did not think that the Constitution would protect personal freedoms nor the states to keep a balance of power among them. So, states like North Carolina, Rhode Island, and Massachusetts only agreed to ratify the Constitution only after they were promised that a bill protecting individual and states rights would be added to it.

Some Federalists said that the nation did not need to add these protections because the Constitution itself was a bill of rights. It was, they argued, written to protect the liberty of all U.S. citizens. However, James Madison, a Federalist, wanted to make a bill of rights one of the new government's first priorities. In Congress's first session, Madison encouraged the legislators to put together a bill of rights. The rights would then be added to the Constitution as amendments, or official changes. In Article V of the Constitution, the founders had provided a way to change the document when necessary in order to reflect the will of the people. The process requires that proposed amendments must be approved by a two-thirds majority of both houses of Congress and then ratified by three-fourths of the states before taking effect.

Legislators took ideas from the state ratifying conventions, the Virginia Declaration of Rights, the English Bill of Rights, and the Declaration of Independence to make sure that the abuses listed in the Declaration of Independence would be illegal under the new government. In September 1789 Congress proposed 12 amendments and sent them to the states for ratification. By December 1791 the states had ratified the Bill of Rights, 10 of the proposed amendments intended to protect citizens' rights.

These 10 amendments set a clear example of how to amend the Constitution to fit the needs of a changing nation. The flexibility of the U.S. Constitution has allowed it to survive for more than 200 years with 27 amendments so far.