The debate over ratification was waged in the newspapers,
through pamphlets, and on the floor of the state conventions, where the vote
was often close. Those who favored the strong national government provided for
in the Constitution called themselves the Federalists;
their opponents became the Antifederalists.
The Antifederalists believed that the Constitution gave too much power to the central government and left the states with too little. Strong proponents of individual liberty, they vigorously criticized the omission of a bill of rights, which was included in many state constitutions. Some considered the ratification process itself illegal, because unanimous consent from the states was required to amend the Articles of Confederation.
The case for the Constitution was effectively presented in a series of newspaper articles that were written by Alexander Hamilton, John Jay, and James Madison, collectively known as The Federalist Papers. The Federalists argued that the new government would not be dominated by any one group and that there were adequate safeguards to protect individuals and the states.
On June 21, 1788, New Hampshire became the ninth state to ratify the Constitution. Two key states — Virginia and New York — gave their approval during the next month. An important factor in swaying the state conventions was a commitment from the Federalists to add a bill of rights after ratification.