What if the Supreme Court had held that the Constitution did not give Congress any general power to restrict immigration (and that it is not an "inherent power" either)? For a defense of this position by an open-borders libertarian, see http://openborders.info/…/immigration-and-the-us-constitut…/ Most likely, of course, if the Court had so held at the time of the Chinese Exclusion cases of the late nineteenth century, the Constitution would have been amended to provide for such a power, but Somin argues that "the Constitution is extremely hard to amend, and it is far from clear that the supporters of the Exclusion Act had the necessary two-thirds majority in both houses of Congress, plus winning the support of three quarters of state legislatures."
Of course any Court taking such a narrow view of Congress' constitutional power in this respect is likely to take a narrow view of it in other respects as well (e.g., if the Commerce Clause doesn't cover immigration, it presumably doesn't cover a great many other things it has been held to cover) but for now let's ignore that, and just focus on immigration.
Of course any Court taking such a narrow view of Congress' constitutional power in this respect is likely to take a narrow view of it in other respects as well (e.g., if the Commerce Clause doesn't cover immigration, it presumably doesn't cover a great many other things it has been held to cover) but for now let's ignore that, and just focus on immigration.