The Anti-Federalist Party was a political group in the early United States that opposed the ratification of the U.S. Constitution in 1787-1788. They believed that the new Constitution gave too much power to the federal government and threatened individual liberties. Prominent figures included Patrick Henry and George Mason, who argued for stronger protections of states' rights and personal freedoms. The Anti-Federalists favored a decentralized government structure, advocating for a Bill of Rights to safeguard citizens' freedoms. Their concerns led to the eventual adoption of the Bill of Rights in 1791, which addressed many of their demands and helped to balance federal and state powers.