The herpes theory of commerce clause jurisprudence
The Volokh Conspiracy has an interesting posting here on the "herpes theory" -- namely, if an article has EVER moved in commerce, Congress can regulate it thereafter -- like herpes, once it's got it, it has it forever.
It cites to a 10th Circuit case that essentially recognizes that the Supreme Court, in a felon in possession case many years ago, endorsed that for the Gun Control Act -- it is sufficient to prove that a felon's gun at some point had moved in commerce. (BTW, it was a terrible Burger decision, that misread the statute in several ways. The statute, on its face, did not bar the conduct involved, but the court made it applicable -- if Congress didn't draft a law the way the Supremes felt it should have been drafted, they were going to correct that). The 10th Circuit noted that this approach to commerce couldn't be reconciled with post-Lopez rulings that say the commerce clause must be met in one of three ways, none of them including "if it has ever moved in commerce." But, the Circuit concludes, Lopez and later cases never overruled the earlier decision, and if the two groups of caselaw are to be reconciled, that's a job for the Supreme Court.
UPDATE: link fixed.