Nolo was born in 1971 as a publisher of self-help legal books. Guided by the motto “law for all,” our attorney authors and editors have been explaining the law to everyday people ever since. Learn more about our history and our editorial standards.
Each article that we publish has been written or reviewed by one of our editors, who together have over 100 years of experience practicing law. We strive to keep our information current as laws change. Learn more about our editorial standards.
1) The principle that a federal law supersedes a state law, or a state law supersedes a local law, when both governments have made laws on the same subject. Preemption can be found when:
the superseding federal or state law expressly preempts conflicting state or local laws, or
the superceding federal or state law is comprehensive and occupies the field, or a conflicting state or local law frustrates the purpose of the superceding law.
2) The right to purchase before others (for example, a preemptive right).