Preemption Legal Meaning and Definition

Here is a simplified definition of the legal term Preemption.

Preemption (noun)

Preemption is a legal principle where a higher authority's laws take precedence over the laws of a lower authority when there's a conflict between the two. In the United States, if a federal law conflicts with a state law, preemption causes the federal law to 'overrule' or 'win over' the state law, making the state law ineffective.