A Constitutional Convention was held to address these problems. After much debate, the decision was made to create a new constitution. The development of the U.S. Constitution required many compromises among the state representatives. Concern over the power of the federal government and the protection of individual rights made the ratification of the Constitution uncertain. In order to gain Anti-Federalist support to ratify the Constitution, the Federalists agreed to add a Bill of Rights, guaranteeing the protection of individual rights.
(Hopefully this helps!)