Conflict preemption occurs when federal and state laws cannot coexist because following both simultaneously is impossible, or state law stands as an obstacle to federal objectives. When conflict is unavoidable, the Supremacy Clause means federal law wins and state law is void.
Courts ask whether compliance with both laws is physically possible or whether state law interferes with federal goals. Texas's attempt to arrest migrants for illegal entry conflicted with federal immigration law that reserves deportation authority to federal agencies. State law couldn't coexist with federal authority.
Conflict preemption differs from field preemption (where federal law occupies an entire area) or obstacle preemption (where state law doesn't directly conflict but frustrates federal purposes). The most straightforward form occurs when state and federal law directly contradict each other.
Conflict preemption prevents states from paralyzing federal authority. If states could enforce competing rules in federal domains like immigration and banking, uniform national policy would be impossible.
People often think preemption is automatic whenever federal and state law exist on the same topic. Many areas have both federal and state law operating simultaneously. Preemption only applies when genuine conflict makes both rules impossible to follow.
Conflict preemption prevents states from paralyzing federal authority. If states could enforce competing rules in federal domains like immigration and banking, uniform national policy would be impossible.
People often think preemption is automatic whenever federal and state law exist on the same topic. Many areas have both federal and state law operating simultaneously. Preemption only applies when genuine conflict makes both rules impossible to follow.