The California three strikes law provides authority for prosecutors to seek, and for judges to impose, a prison sentence that is doubled for an adult convicted of any felony if the defendant has a first strike on his or her record. A strike is associated with serious or violent felony convictions, and the law recognizes serious or violent felony convictions of 16 or 17-year-old defendants in juvenile court.

Cases in juvenile court are tried before a judge without a jury. Supreme Court precedent says that a criminal defendant has the right to a jury trial on any fact that is used to increase a jail or prison sentence.

A San Jose man pled guilty to residential burglary in 2010. Prosecutors pulled out a prior robbery conviction that was rendered in juvenile court when the man was 16. That conviction involved allegations that the juvenile took $117 in a robbery of an ice cream vendor. The case in juvenile court was not presented to a jury. Prosecutors used the juvenile conviction as a first strike in seeking a doubled sentence for the 2010 adult conviction.

The judge imposed an eight year sentence in the 2010 adult conviction, based upon the juvenile case. The man appealed his sentence, arguing that the state could not increase his 2010 sentence under the three strikes law based upon the juvenile conviction because the allegations in the juvenile court case had not been proven to a jury beyond a reasonable doubt. California courts upheld the man's sentence, reasoning that the defendant could have sought a jury trial in the juvenile case.

The United States Supreme Court denied review of the case Monday, allowing the California ruling to stand.

Source: San Francisco Chronicle, "Court: Juvenile case still counts in three strikes," Bob Egelko, May 22, 2012