Final answer:
Anti-Federalists refused to accept the Constitution without a Bill of Rights. Federalists won their support by promising to add these crucial amendments, which ensured protections for individual liberties.
Step-by-step explanation:
The one thing that Anti-Federalists would not budge on was the lack of a Bill of Rights in the Constitution. The Anti-Federalists strongly believed that, without such protections, the power granted to the federal government would come at the expense of individual liberties and feared it would lead to tyranny.
The Federalists finally won them over by promising to add a Bill of Rights that would safeguard individual liberties, which was a pivotal move to secure broader support for the Constitution's ratification. This promise was fulfilled with the adoption of the first ten amendments, now known as the Bill of Rights, after the Constitution went into effect. To win over the Anti-Federalists, the Federalists promised to add a bill of rights to the Constitution. This assurance helped convince many Anti-Federalists that their concerns would be addressed.