Damian McElrath was tried for murdering his adoptive mother. The jury found him guilty of felony murder but not guilty of malice murder by reason of insanity. Georgia wanted to retry him on the malice murder charge, claiming the verdicts were inconsistent. In February 2024, the Supreme Court unanimously said no.
The Fifth Amendment blocks the government from trying you twice for the same offense after a jury has decided your fate. Get acquitted and you walk free forever on that charge, even if new evidence emerges. Get convicted and you can appeal, but the government can't appeal an acquittal even when the jury makes obvious mistakes. The protection has limits—a mistrial or hung jury doesn't count as jeopardy, so prosecutors can try again. And the dual sovereignty doctrine means both federal and state governments can prosecute you for the same conduct, because they're separate sovereigns enforcing separate laws.