The most signficant impact of the anti-federalists on the Constitution was the implementation of the Bill of Rights.
Anti-federalists were concerned that the new US Constitution gave too much power to the federal government. Anti-federalists argued that a strong central (aka federal) government would result in tyranny, just like it did when America was still part of the British empire. This is why the anti-federalists wanted a list of rights that all American citizens can possess. This list of rights would check the power of the federal government and prevent the government from restricting the rights of citizens.
The main impact of the Anti-Federalists on the adoption of the US Constitution was their concern for preserving liberty led to the inclusion of the Bill of Rights in the ratified form of the Constitution.
Anti Federalists were against strong government, and wanted a Bill of Rights as oppose to the Federalists.
The Bill of Rights amendments introduced to the Constitution particular guarantees of personal freedoms and rights, specific limitations on the government's power in judicial and other proceedings, and clear declarations that all powers not specifically granted to the U.S. Congress by the Constitution are reserved for the states or the people.
The "elastic," or implied powers, clause gives Congress the authority to pass laws it deems "necessary and proper" to carry out its enumerated functions.
