In U.S. v. Aviles, No. 05-14446 (March 4, 2008), the Court, on a government appeal, reversed the district court for possibly using the wrong Guidelines manual at sentencing.
A sentencing court should apply the Guidelines manual in effect at the time of sentencing, unless use of this manual would violate the Ex Post Facto Clause (because the punishment increased after the defendant committed the offense), in which case it should use the manual in effect at the time the crime was committed. This rule can raise issues in conspiracy cases, where the crime continues over time, somewhat indefinitely. Was the defendant still involved in the conspiracy at the time of the later manual? Or did he withdraw? Can the reasonably foreseeable acts of his co-conspirators extend the conspiracy, even if he withdrew, since these acts are part of the defendant’s "relevant conduct"? Are the acts of a co-conspirator reasonably foreseeable when the conspiracy itself is sporadic?
The Court held that only when a conspiracy is "sporadic" can the cessation of one defendant’s participation cut-off the time for applying a new Guidelines manual. When (as here) a conspiracy is constant and consistent, then only withdrawal from the conspiracy will avoid application of a new Guidelines manual (under ex post facto principles). Here, the district court failed to address the withdrawal question. The Court therefore remanded the case for consideration of when the defendants withdrew from the conspiracy.