Federalism is a system of government in which power is, within the constitution, divided between a central authority and constituent political units. They work independently but share sovereignty.
There are three parts of federalism; delegated powers, reserved powers, and concurrent powers. Delegated powers are the powers given to the federal government by the constitution. Reserved powers are set for the states and or the people. Finally, concurrent powers are rights shared by both the federal government and the states. Some examples of delegated powers are the responsibility to regulate foreign trade, the control of currency, and to control the armed forces. All of the things that are required to be the same in the entire nation are things that the delegated powers need to do.
This way all things that should be made federal laws and that should be the same in every state are. Reserved powers, the responsibilities of the states, are things like controlling local business, controlling local elections, and establish local governments. These things are going to be done different by all states, but they should be working together from state to state to make sure they can work along with each other, and trade with each other. Concurrent powers, or shared powers, are things that both the states and the federal government are responsible for taking care off, such as collecting taxes and giving grants, law enforcement, and health and welfare systems. Also, establishing a court system to work in order and along with other courts is also something that both the federal government and the state governments are required to regulate.