In researching statistics for an unrelated article, I came across yet another reason for individual states — and particularly Arkansas — to crack down on illegal immigration: methamphetamine.

According to the National Drug Intelligence Center’s Drug Threat Survey, law enforcement officials in Arkansas reported in 2002 that the drug is one of the biggest and most serious threats in the state.

Five years later, that finding was reaffirmed by the Office of National Drug Control Policy, which called meth “the primary drug of concern” in the state.

And it’s also...