Believe it or not, over 230 years after the Constitution was adopted, law professors and judges still argue over whether the Constitution gives Congress power to control immigration—and, if it does, the clause of the Constitution that grants that power.
The dispute is a measure of just how slapdash most legal “scholarship” is.
But that dispute is now (hopefully) over. A new article published in a peer-reviewed journal by Rob Natelson, II’s Senior Fellow in Constitutional Jurisprudence, answers the question: The Constitution does, indeed, give Congress and the President power to prevent people from flooding over American borders—if they choose to exercise it. Further, we know that the authority comes from Article I, Section 8, Clause 10 of the Constitution, which grants power to “define and punish . . . Offenses against the Law of Nations” (and crossing a border illegally is one such “Offense”).
To arrive at this answer, Rob did something too few legal researchers do: Instead of speculating on the issue, he examined books of international law widely used among the founding generation. They provided the answer. You can read the article yourself here.