Lopez v. Gonzales:
Today the Supreme Court held, 8-1, in Lopez v. Gonzales that conduct made a felony under state law is not a “felony punishable under the Controlled Substances Act” that could trigger deportation under the Immigration and Naturalization Act if it is not punishable as a felony under the CSA. Justice Souter wrote the majority opinion. Justice Thomas dissented "[b]ecause a plain reading of the statute would avoid the ambiguities and anomalies created by today’s majority opinion." SCOTUSBlog has more here.
The majority says the phrase refers to crimes that the CSA categorizes as felonies. Thomas says the phrase refers to all felonies (state or federal) that the CSA punishes at all, whether or not they are punished in the CSA as misdemeanors or felonies.
Thomas has a bunch of throwaway arguments. The word "any" modifying the word "felony" should always be interpreted broadly. Uh, sure, with respect to its referent - but you still have to figure out what the referent is, i.e. the question above. Using "any" (the modifier) to figure out the referent (the correct interpretation of "felony punishable under the CSA") is a textbook example of putting the cart before the horse.
I think he scores his best points on the majority with the argument about Section 924(c)(1)(A) containing the language "for which hte person may be prosecuted in a court of the United States." (c)(2) doesn't have that, so I guess maybe he's got a Russello point about the absence of qualifying language in a similar context. But then again, (c)(2) expressly incorporates the CSA, which self-defines as a federal question, so I'm not sure why (c)(2) would need the jurisdictional language in (c)(1) (which applies to drug trafficking crimes generally, a subset of which are state offenses).
His structural arguments are interesting, but the reading of the statutory language, "felonies punishable under the CSA" seems pretty clear, unless you can mount overwhelming structural evidence showing that state felonies punished by the CSA only as misdemeanors were contemplated by the statute.
A more cynical reader might point out some of the inconsistencies that reveal themselves when you compare the "of course possession [does/does not] equal trafficking" in this context with that issue in others (ahem, commerce clause). But only a cynical reader might do that.