Ann Coulter

But then she also sued the drug manufacturer, Wyeth Laboratories, on the grounds that it should have included more glaring warnings about proper administration of the drug -- like, I don't know, maybe a flashing neon sign on each vial.

Wyeth argued that since the Food and Drug Administration (after 54 years of study) had expressly approved the warnings as provided, state tort law was pre-empted by the federal drug regime.

But the Supreme Court held that Congress had to make pre-emption explicit, which it had not, so Levine was awarded $6.7 million from Wyeth.

If ever there were a case for "implicit pre-emption," this was it. Without federal supremacy for the FDA's comprehensive regulation of drugs, pharmaceutical companies are forever at the mercy of state and local laws -- and trial lawyers -- in all 50 states.

As much as I would like pharmaceutical companies to rot in hell for their support of ObamaCare, I might need their drugs someday. Now, drug prices will not only have to incorporate R&D costs, but also the cost of paying for trial lawyers' Ferraris. (Perhaps that should be listed as a side effect: "Caution! Improper use may cause nausea, dizziness, shortness of breath, and six new houses for John Edwards.")

But the point is: According to the Supreme Court's most recent pre-emption ruling, Arizona's law is not pre-empted because Congress did not expressly prohibit state regulation of illegal aliens.

In fact, the Supreme Court has repeatedly rejected the pre-emption argument against state laws on immigrants -- including laws somewhat at odds with federal law, which the Arizona law is not.

In the seminal case, De Canas v. Bica (1976), the court held 8-0 that a California law prohibiting employers from hiring illegal immigrants was not pre-empted by federal law.

The court -– per Justice William Brennan -- said that the federal government's supremacy over immigration is strictly limited to: (1) a "determination of who should or should not be admitted into the country," and (2) "the conditions under which a legal entrant may remain."

So a state can't start issuing or revoking visas, but that's about all it can't do.

Manifestly, a state law about illegal immigrants has nothing to do with immigrants who enter legally or the condition of their staying here. Illegal aliens have neither been "admitted into the country" nor are they "legal entrants."

Indeed, as Brennan noted in the De Canas case, there's even "a line of cases that upheld certain discriminatory state treatment of aliens lawfully within the United States." (You might want to jot some of this down, Mr. Holder.)

So there's no "field pre-emption" of state laws dealing with aliens, nor is there an explicit statement from Congress pre-empting state regulation of aliens.

On top of that, the Supreme Court has repeatedly upheld state laws on immigrants in the face of pre-emption challenges. Arizona's law is no more pre-empted than the rest of them.

Unless, of course, Obama is right and it's a violation of federal law to enforce federal immigration laws, which is the essence of the Department of Justice's lawsuit.