The two sides in the fight for the ratification of the U.S. Constitution were the Federalists, who supported it, and the Anti-Federalists, who opposed it. Alexander Hamilton, James Madison and John Jay were three noted Federalists, while Patrick Henry, James Monroe and George Clinton were famous Anti-Federalists.
The Anti-Federalists had a number of qualms about the new governing document. First of all, they believed that it gave the new central government and the president who headed it too many powers at the expense of powers traditionally held by the states. Some believed that the Constitutional Convention had drafted it illegally. Others believed that it favored elites at the expense of the common people. Many criticized its lack of a bill of rights.
The Federalists wrote a series of articles, "The Federalist Papers," to allay these fears, and they promised to adopt a bill of rights for the new Constitution.