That a defendant may not be retried following an acquittal is "the most fundamental rule in the history of double jeopardy jurisprudence". "The law attaches particular significance to an acquittal. To permit a second trial after an acquittal, however mistaken the acquittal may have been, would present an unacceptably high risk that the Government, with its vastly superior resources, might wear down the defendant so that 'even though innocent he may be found guilty'". While in other areas of double jeopardy doctrine consideration is given to the public-safety interest in having a criminal trial proceed to an error-free conclusion, no such balancing of interests is permitted with respect to acquittals, "no matter how erroneous," no matter even if they were "egregiously erroneous."
The acquittal being final, there is no governmental appeal constitutionally possible from such a judgment.