Constitutional Law I
Field Preemption occurs when federal law leaves no doubt that Congress intended to occupy an entire field.
This can be detected in several ways:
- The federal regulation being so pervasive to imply that Congress intended to displace state regulatory authority
- The federal law touches a field in which the federal interest is so dominant that the federal system is assumed to preclude enforcement of state laws on the subject
- The object sought to be obtained by the federal law and the character of obligations imposed by it reveal a congressional intent to fully occupy the field
Impossibility conflict preemption occurs when compliance with both state and federal law is literally impossible.