Which political group from the late 1780s believed in states' power within the U.S. government — the Republicans, Democrats, Federalists, or Anti-Federalists?

The political group from the late 1780s that believed strongly in states' power within the U.S. government were the Anti-Federalists. They opposed the centralization of power and were skeptical about the lack of protection for individual rights in the original Constitution. In contrast, the Federalists were proponents of a stronger central government.

The Anti-Federalists and Federalists represented the two main political ideologies of the time regarding the ratification of the United States Constitution. The Federalists, including figures like Alexander Hamilton, John Adams, and James Madison, argued for a strong federal government that could unite the states and efficiently manage the country's affairs. The Anti-Federalists, such as Patrick Henry, George Mason, and Thomas Jefferson, feared that such a powerful federal government could become tyrannical and infringe upon the rights and sovereignty of the states.

As a result of the Anti-Federalist movement, the Bill of Rights, consisting of the first ten amendments to the Constitution, was introduced and ratified, ensuring protection for individual liberties and addressing many concerns raised by the Anti-Federalists about the potential for government overreach. The political dialogue between these two groups was crucial in shaping the early political landscape of the United States and reflects a continuing debate about the balance of power between state and federal governments.