Recent Supreme Court precedents have suggested that an error in calculating the advisory Guidelines range will rarely be harmless error, even under a plain error standard of review. See MolinaMartinez
v. United States, --- U.S. ---, 136 S. Ct. 1338, 1346 (2016). The Sixth Circuit found such a rare occasion in United States v. Susany, found here.
In Susany, the district court committed error by not reducing by three levels the base offense level under U.S.S.G. § 2X1.1. The Court found that the district court should have given the reduction, as although the defendant was involved in a conspiracy to break into jewelry stores, the defendant and his co-conspirators had not yet taken many of the steps necessary in order to actually commit the offense. "A reduction pursuant to § 2X1.1 may be denied only if all crucial steps for committing the substantive offense either have already been completed or the co-conspirators would have been capable of the commission of the substantive offense within a negligible intervening time."
But the Court found such error to be harmless - the Court noted "Susany’s case thus falls within a very unusual circumstance—the district court’s error resulted in a lower advisory sentencing range than would have resulted under the correct Guidelines calculation. We are also persuaded that the district court indicated that it provided Susany a downward variance based on the nature and circumstances of the offense, giving him “what [he] asked for; in a different way.” In this rare situation, the error did not cause Susany to receive a more severe sentence than he would have received without the error."