Federalism is a political philosophy in which a group of people are bound together, with a governing head. In a federation, the authority is divided between the head (for example the central government of a country) and the political units governed by it (for example the states or provinces of the country).
Several countries in the world have a federal government; examples are United States of America, Canada, Nigeria, Australia, India, Brazil, Switzerland, Germany, and Austria. The European Union can be called a sort of federal government as well.
In the United States Constitution for example, the federal government and state governments both have power. When states and the federal government do not agree on something, the federal government can sue the state in court using the Supremacy Clause in Article VI of the Constitution. This case can go as far as the Supreme Court to decide which side is right. The federal government does not always do this. It has taken no action when several states made marijuana legal or when prostitution was made legal in parts of Nevada. It has sued over an immigration law in Arizona.
- "What happens when a state law contradicts a U.S. federal law?". HowStuffWorks. 2012-12-10. Retrieved 2022-05-03.