In the case of United States v. Atkinson, the Supreme Court ruled in favor of Atkinson, who was charged with smuggling alcohol into the U.S during Prohibition. The court found that there had been an error in his trial because he was not allowed to cross-examine a key witness for the prosecution - a customs agent who testified about finding liquor on Atkinson's boat. The Sixth Amendment guarantees defendants' right to confront their accusers and this includes being able to question them at trial. Therefore, denying him this opportunity violated his constitutional rights and led to an unfair trial outcome.

In the dissenting opinion for United States v. Atkinson, Justice Stone argued that the majority's decision to reverse and remand the case was incorrect because it failed to consider whether or not there was sufficient evidence presented at trial to support a conviction. He believed that if such evidence existed, then any error made by the lower court in admitting additional evidence would be harmless and should not result in a reversal of judgement. According to him, an appellate court has both power and duty under federal law (section 269 of Judicial Code) to examine record for purpose of determining whether judgment below is reversible error due its harmful effect on substantial rights of parties involved; this includes assessing sufficiency of proof without regard to erroneously admitted evidences. Therefore, he disagreed with majority’s view which refrained from examining entire record before reversing judgment based solely on one alleged mistake during proceedings.