Good lord! If you graduated law school, you were almost certainly exposed to the Court's Dormant Commerce Clause jurisprudence, and even if you don't know all the details, you would know that the gist of the doctrine is that, because the Founders were concerned about the states engaging in interstate economic warfare, they gave Congress comprehensive legislative control over interstate commerce, and impliedly prohibited the states from engaging in protectionism or other activities that harmed interstate commerce.
If you can't say at least that much, then you shouldn't be sitting on a federal court as a judge, period.