Question

Why is the Supremacy Clause considered to be “the root of federalism”?

Answer 1

The reason why the Supremacy Clause is considered to be “the root of federalism” is because it holds that the federal government is ultimately more powerful than the individual states--which unites the states into a single entity. 

Answer 2

The answer is It describes the relationship between federal and state power.

The Supremacy Clause, found in Article VI, Paragraph 2 of the U.S. Constitution, establishes that all federal laws are the supreme law of the land and therefore all states, federal officers and judges are bound by it, meaning that in case of a conflict between state and federal laws, the federal laws is the one that shall prevail.

By describing this relationship between federal and state power, in which federal law takes preference over state law, the Supremacy Clause established the root of federalism.