United States v. McMillan, Slip Copy, WL 3206535 (8th Cir. Aug. 9, 2012) (court enforced an appeal waiver where defendants brief did not articulate the error in terms of a violation of any constitutional right; the issue was limited to plain error because no objection had been lodged at the time of the sentencing hearing).

Note: To raise appellate challenges to unforeseen errors by the district court at the sentencing hearing for a defendant whose guilty plea agreement included an appellate waiver, defendant must couch the sentencing court's error as a constitutional violation and object to the error in the district court. In declining to articulate any predictable rule being applied in these cases, the Eighth Circuit's almost whimsical approach to whether and when to enforce an appeal waiver -- reducing the analysis to ad hoc judgments that either enforce appeal waivers or "elect to bypass the possibility of [such] waiver[s]" -- may itself raise questions about due process and equal protection of the law in the Eighth Circuit.