What is the test for reversing a jury's verdict in a criminal case when the jury found that the prosecution failed to prove all elements beyond a reasonable doubt?

In attempting to determine what standard the jury actually applied, we cannot focus exclusively on a few erroneous words in the jury instruction and then reverse the conviction unless it is "reasonably likely" that the jury applied the erroneous standard described or implied by those few words. We must examine the overall charge that the jury heard for a better view of the standard the jury took into its deliberations and applied. United States v. Park, 421 U.S. 658, 674, 95 S.Ct. 1903, 1912-13, 44 L.Ed.2d 489 (1975) ("a single instruction to a jury may not be judged in artificial isolation, but must be viewed in the context of the overall charge" (quoting Cupp v. Naughten, 414 U.S. 141, 146-47, 94 S.Ct. 396, 400, 38 L.Ed.2d 368 (1973))).

Sometimes, erroneous portions of the jury instructions are offset when considered in context or explained by the trial court in later sections of the instruction. Park, 421 U.S. at 674-75 & n. 16, 95 S.Ct. at 1912-13 & n. 16 (holding that, among other things, the prosecutor's summation put the challenged portions of the jury instructions into the proper light). Other times, a seemingly innocuous incorrect statement becomes extremely damaging when coupled with other sections of the jury instructions or with improper conduct by counsel during the trial. United States v. Birbal, 62 F.3d 456, 462 (2d Cir.1995) (holding that trial court's statement that jury may acquit the defendant if prosecution fails to prove all elements beyond a reasonable doubt made a bad but non-reversible jury charge reversible). Thus a challenged portion of the jury instructions "may not be judged in artificial isolation," Cupp, 414 U.S. at 147, 94 S.Ct. at 400, but rather must be judged as the jury understood it, as part of the whole instruction, and indeed, as part of all the proceedings that were observed by the jury.