"The power to determine whether a case should be heard as a juvenile proceeding or a criminal proceeding is an important one, affecting generations of youth to come, that cannot be stripped from judges and placed solely in the hands of prosecutors," said Robert Kim, staff attorney at the ACLU of Northern California. "To do so violates core separation-of-powers and due process principles."

Steve Mayer, a partner at the San Francisco law firm of Howard, Rice, Nemerovski, Canady, Falk & Rabkin, added, "For the prosecution to have the power, without any standards, to send two youths accused of committing the same offense to entirely different courts with entirely different sentencing powers violates equal protection and the constitutional requirement that laws be uniform."

In addition, the ACLU states that Proposition 21 is unconstitutional because it contains more than a single subject, and because it contains text that is different from the text circulated among voters for signature in 1998 in order to qualify the measure for the ballot.

The lawsuit, League of Women Voters of California v. Gray Davis, was filed on behalf of the League of Women Voters of California, Children's Advocacy Institute, Coleman Advocates for Children and Youth, and Peter Bull, former director of a Bay Area youth organization. The lawsuit is brought by the California ACLU affiliates and the law firm of Howard, Rice, Nemerovski, Canady, Falk & Rabkin.