United States v. Savoy, Docket No. 08-4900-cr (2d Cir. May 27, 2009) (found here)
The Second Circuit (including Judge Sotomayor) considered the question of whether Section 1B1.10 of the Guidelines (the Sentencing Commission's policy statement regarding the reduction of sentences pursuant to an amended Guidelines range) precludes sentencing a defendant below an amended Guidelines range.
Specifically, Section 1B1.10 of the Guidelines provides that courts may reduce a defendant's sentence if the Sentencing Commission subsequently reduces the applicable Guidelines range of imprisonment. It further provides that a district court, when considering whether a reduction is warranted, "shall determine the amended guideline range that would have been applicable to the defendant if the amendment(s) to the guidelines . . . had been in effect at the time the defendant was sentenced." And it provides that, save for exceptions not applicable to Savoy, "the court shall not reduce the defendant's terms of imprisonment [in crack cocaine cases] to a term that is less than the minimum of the amended guideline range . . . ."
Thus, the question before the Second Circuit was "[w]hether courts are required to construe the 'shall not' language of Section 1B1.10(b)(2)(A) as advisory rather than mandatory in light of Booker and its progeny" -- an open question in the Second Circuit. Joining several of its sister circuits, the Second Circuit found that it is not required to consider it advisory. Rather, the Second Circuit held that Section 1B1.10 is "binding on sentencing courts," and held that "district courts lack the authority when reducing a sentence pursuant to [Section] 3582(c)(2) to reduce that sentence below the amended Guidelines range where the original sentence fell within the applicable pre-amendment Guidelines range."