Modified Categorical Imperative

I am pleased by Descamps.  Like many people to have clerked on courts with a sizable criminal docket, I have spent a lot of time thinking about the so-called "categorical approach" to sentencing, and what Justice Kagan calls the "not very inventively" labeled "modified categorical approach."  If you don't know what this is, it probably isn't worth your time to learn it, but the gist of it is a formalistic, frequently misunderstood approach to determining when a defendant has a prior conviction for purposes of the Armed Career Criminal Act and other similar statutes, instigated by a case called Taylor.  Anyway, in keeping with the prior format:

• This is the most correct thing the Court has written about the categorical approach since Taylor itself.
• That said, I am still unsatisfied with pages 16-19, where the Court tries to explain the difference between alternative elements of a crime and alternative means of committing the same crime.  The Court seems to link this test, for modified categorical approach purposes, to the rules about juror agreement on alternative theories of the crime.  ("Seems" because the dissent, but not the majority, cites Schad and Richardson.)  That might be right, but I know enough to know that it's a complicated area where the Court's precedents are unsatisfying.  And if Steve Sachs is right about how to think about alternative theories of the crime, then it's an unpromising fulcrum from which to move the modified categorical approach.
• This is not a decision about burglary.  It's a broad statement about the modified categorical approach and a big change in what I've seen from many judges' thinking in this area.
• I also find it moderately surprising that the opinion purports to "reserve" the question of whether to "take account not only of the relevant statute’s text, but of judicial rulings interpreting it," which many people had thought was uncontroversial.
• If you are interested in sharp-tongued judicial rhetoric, you should be following Justice Kagan.  The opinion positively mocks the Ninth Circuit decision, Aguila-Montes de Oca, that is substantively reversed in this case. ("When assessed in light of those three reasons, the Ninth Circuit strikes out swinging." "Similarly, consider (though Aguila-Montes did not) ..." "The Ninth Circuit defended its (excessively) modified categorical approach ..." "Here is the only conclusion in Aguila Montes we agree with:")
• For a long time, every time I thought I had a useful article to write about the modified categorical approach, the Court would ruin it with a new (problematic) decision.  For once, I feel like it is moving wholly in the right direction.