Final answer:
The dormant commerce clause suggests that state laws should not place undue burdens on interstate commerce and may be struck down if they do, unless the state has a substantial reason that outweighs the impact on trade.
Step-by-step explanation:
How the Dormant Commerce Clause Affects State Law
The dormant commerce clause refers to the concept that state laws should not unduly burden interstate commerce. Even though the U.S. Constitution does not explicitly mention a "dormant" commerce clause, the principle is inferred from the Commerce Clause in Article I, Section 8, which grants Congress the power to regulate commerce among the states. This implies a negative aspect; that states should not pass legislation that heavily impairs interstate trade.
The Supreme Court has historically used the dormant commerce clause as a means to promote economic unity and limit state parochialism. As early as Gibbons v. Ogden (1824), the Court has affirmed the supremacy of federal power over commerce among the states. However, cases like United States v. E. C. Knight and United States v. Lopez show that there are bounds to this power and instances where state sovereignty is respected, especially when activities being regulated by Congress under the commerce clause do not substantively affect interstate commerce.
Generally, when a state law is challenged under the dormant commerce clause, the Court will assess whether the law discriminates against interstate commerce in favor of in-state interests, and whether it serves a legitimate local purpose that could not be adequately served by reasonable non-discriminatory alternatives. If a law excessively burdens interstate commerce, it is likely to be struck down unless it is proven that the state has a compelling interest that justifies the burden and there are no other means to achieve that interest.
In summary, the dormant commerce clause operates as a constraint on state legislation, ensuring that states do not enact regulations that disrupt the national market or hinder the free flow of trade across state borders.