Whether the first jury's conviction of Green for second-degree murder, coupled with its silence on first-degree murder, barred a later prosecution for first-degree murder after the jury was discharged.
Holding
Yes. The first proceeding ended Green's jeopardy for first-degree murder, and the second trial on that charge violated the Double Jeopardy Clause.
Reasoning
The Fifth Amendment protects an accused not merely from multiple punishments, but from the ordeal and risk of repeated trials for the same offense. The protection prevents the State, with its superior resources, from making successive efforts to convict, thereby imposing anxiety, expense, embarrassment, and an increased risk that an innocent person will eventually be convicted.
At the first trial, Green faced a direct risk of conviction and death for first-degree murder. The jury was expressly authorized to choose between first-degree and second-degree murder, but chose the latter. That choice was properly treated as an implicit acquittal of first-degree murder, just as if the verdict had expressly said that Green was not guilty of first-degree murder but guilty of second-degree murder.
Even apart from the implicit-acquittal doctrine, the result followed from the jury's discharge. The jury had a full opportunity to return a first-degree-murder verdict, no extraordinary circumstance prevented it from doing so, and it was discharged without Green's consent. Under established double-jeopardy principles, jeopardy on the unresolved first-degree charge therefore terminated when the jury was dismissed.