What is the main difference between federal and confederal systems of government?

The main difference between the federal and confederal systems of government lies in who has the power.

In a federal system of government, there is a strong central government which has the majority of the power. In a confederal system, the central government is quite weak and the entities that making up the confederation, such as states, are the ones with all the power. When the United States switched from the Articles of Confederation to the U.S. Constitution, the federal government was given much more power than the central government had under the Articles of Confederation.

The basic difference is that confederalism is a system where the central government is always quite weak whereas in federalism the central government can be quite a bit stronger.

Explanation:

missouri compromise of 1820 which prohibited slavery