What is the harmless error analysis that a reviewing court should use when a trial court's jury instructions incorrectly define an element of a charged offense?

Although this was the most recent case in which the United States Supreme Court has explained the harmless error analysis that a reviewing court should use when a trial court's jury instructions incorrectly defined an element of a charged offense, and although the holding in that case has not been expressly overruled, there are grounds to doubt that the harmless error analysis set forth in the majority opinion in Pope v. Illinois, supra, 481 U.S. 497, 107 S.Ct. 1918, has continuing vitality as precedent.