Definition - What does Supremacy Clause mean?
The Supremacy Clause is a provision mentioned under Article VI of the United States Constitution, stating that federal laws are always superior to state laws. In the case of a conflict, federal laws will always override state laws.
Justipedia explains Supremacy Clause
The idea and principle of federal supremacy was introduced by the Chief Justice John Marshal in 1819. According to this principle, which is still being followed in the cases of Constitutional issues, the ruling of the Supreme Court is binding on all state courts.