On December 16, 2009, the Iowa Supreme Court in its decision In the Interest of Z.S., issued a decision that although delinquency proceedings are not criminal proceedings, double jeopardy applies (as decided in the Supreme Court of the United States' decision Breed v. Jones, 421 U.S. 519, 531 (1975)) once the juvenile court dismisses the State's petition.  The dismissal was an "acquittal" because it resolved the factual elements of the offense charged. An acquittal cannot be reviewed, for error or otherwise, without violating the Double Jeopardy clause.

The State also claimed that the judge had an affirmative duty to include lesser include offenses in its adjudicatory ruling.  The Iowa Supreme Court decided that the juvenile court has the discretion, but not the obligation, to consider any lesser included offenses.