Ratification was more difficult in the populous states of Massachusetts and New York. The debate in Massachusetts was particularly intense. Massachusetts voted 187 to 168 in favor of the Constitution on February 6, 1788, only after the Federalists agreed to recommend amending the Constitution to include protections for individual liberties.

Massachusetts became the first state officially to recommend amendments to the Constitution during the ratification process. Though the nine proposed amendments bear little resemblance to the final U.S. Bill of Rights, they were an important precursor to the Bill of Rights.