Thus the question was not whether the states were “preempted” from regulating or prohibiting the activities of non-citizens within their territory. It was whether the national government had any power over immigration enforcement. The “unquestionable” power was state power. That is why, in its 1837 New York v. Miln decision, the Supreme Court upheld a state law that allowed New York City to expel arriving aliens it deemed likely to become a public burden. As Justice Philip Barbour explained, the state had acted
to prevent her citizens from being oppressed by the support of multitudes of poor persons who come from foreign countries without possessing the means of supporting themselves. There can be no mode in which the power to regulate internal police could be more appropriately exercised. New York, from her particular situation, is perhaps more than any other city in the Union exposed to the evil of thousands of foreign emigrants arriving there, and the consequent danger of her citizens being subjected to a heavy charge in the maintenance of those who are poor. It is the duty of the state to protect its citizens from this evil; they have endeavored to do so by passing, amongst other things, the section of the law in question. We should, upon principle, say that it had a right to do so.
The oppression then faced by New Yorkers pales in comparison to what is happening in modern Arizona, where — in addition to heavy charges for the subsistence, education, and medical needs of an exploding illegal alien population — citizens are besieged by the militias and drug gangs of a disintegrating Mexico. Yet, from its original posture of great difficulty identifying a source of federal authority over immigration enforcement, the Supreme Court suddenly decided, with the dawn of the Progressive era, that the national government had somehow become preeminent
in the field.
That is the tack taken by Chief Justice Roberts, joined in the Whiting majority by Justices Scalia, Kennedy, Alito, and, with some apparent but unexplained reservations, by Justice Thomas (who concurred in the judgment but joined in only parts of Roberts’s opinion). Arizona’s law enabling the state government to revoke the licenses of businesses that knowingly hire illegals was upheld, but only because Congress had expressly permitted the states to enact such regulations. Arizona’s requirement that all state employers use the federal E-Verify system to ensure that applicants are entitled to work was likewise upheld, but only because Congress had not barred the states from imposing such a requirement, and because the executive branch (during the Bush administration) had characterized Arizona’s E-Verify mandate as “permissible.”
Plainly, the Court’s unanimous position is that the federal government, in its unfettered discretion, may prevent the states from conducting any immigration enforcement, no matter how threatened the states may be by illegal immigration and no matter how resolutely the president refuses to address such threats. The justices divide only over whether the federal government has already prohibited state action; the dissenters (Justices Breyer, Ginsburg, and Sotomayor) contend that it has, implicitly if not explicitly. There is no reason to think Justice Kagan would not have voted with them.
This leaves the states at the mercy of Big Brother for their internal defense, and that is a huge problem. The right of self-defense is a core aspect of sovereignty. If the states no longer have it, they are no longer sovereign, meaning the foundational assumption of our constitutional system no longer obtains.
On the right, commentators are gliding past this looming catastrophe and focusing on the good done by the ruling. To be sure, the validation of a state’s ability to shut down the employment magnet is essential if illegal immigration is to be reduced from a crisis to a nuisance. But this judicial validation is based on the whim of Congress rather than the inherent power of sovereign states. That is not very reassuring: If the years 2007 through 2010 taught us anything, it is that a Congress in the grip of ideology can and will govern against the will of the majority.