In United States v. Flores-Mejia, the en banc U.S. Court of Appeals for the Third Circuit implemented a new requirement to preserve a sentencing error for appeal. Now, if "a party has an objection based upon a procedural error in sentencing but, after that error has become evident, has not stated that objection on the record" during the sentencing hearing, then the Third Circuit will review it only for plain error. Previously, as long as a sentencing argument was raised in the district court - even in a sentencing memorandum filed before the sentencing hearing - but was rejected by the district court at the hearing, on appeal it was reviewed for "reasonableness." Not anymore. After Flores-Mejia, anyone being sentenced who fails to note their objection to a procedural error at the sentencing hearing will have to clear the higher hurdle of plain-error review on appeal. Notably, this new rule applies to procedural errors only, i.e., "a court's failure to give meaningful review to a defendant's substantive arguments," but not to substantive errors, i.e., the length of the sentence imposed. In announcing this rule, the Third Circuit joins the First, Fifth, Sixth, Eighth, Ninth, Tenth and D.C. Circuits, but perpetuates the split with the Fourth Circuit.