A voter-approved law, numbered as Proposition 83 on the ballot, and which prohibits sex offenders from living in 2,000 feet of a school or park is additional punishment for an offender’s original crimes according to a ruling by a state appeals court. The decision could set a precedent that affects thousands of parolees.

On Wednesday the Fourth District Court of Appeal in Santa Ana ruled for the first time in California that residency restrictions laid out by Prop. 83, which was conceived in November 2006, are more than public safety measures; they punish offenders by forcing them out of their homes.

According to the court Jessica’s Law, as it’s called by its supporters, amounts to "traditional banishment under another name." The court ruled that the law will remain in effect but its application could be limited. Retroactively imposing criminal penalties or increasing punishment for a crime already paid for.

Ernest Galvan, an attorney representing four men who’re disputing the proposition before the state Supreme Court said on Thursday that the ruling shouldn’t allow the state to impose residency restrictions on parolee offenders who committed sex crimes before the ballot vote was passed.

Galvan said that the state is applying the 2,000 foot restriction to any former sex offender who has been paroled since Jessica’s Law passed, even if the crime was committed years before, and he was serving a sentence and being paroled for an unrelated crime. At least 2,000 parolees are in that precise situation, and their numbers are growing each month.

"You can't criminalize conduct after it's already happened, can't increase the punishment, because everyone's entitled to notice of what's criminal now," said Galvan.

Gov. Arnold Schwarzenegger’s spokeswoman Lisa Page said the ruling was being reviewed by the administration. “The governor strongly supports Jessica's Law and keeping families and children safe," she said.

Proposition 83 was approved by 70% of voters, and increased sentences for various sex crimes, in addition to forbidding registered sex offenders – committers of anything from forcible rape to indecent exposure – to live within 2,000 feet of a school or park where children gather.

This increases the previous restriction required by state law against a child molester living within a quarter-mile of a school. Prop. 83 effectively makes all densely populated areas of California denied to paroled sex criminals, this includes nearly all of San Francisco.

While it was initially intended to apply the restriction to all 90,000 registered sex offenders in the state, a federal judges’ ruling made the law not cover anyone paroled before Proposition 83 passed.

The four parolees appealing to the Supreme Court call the restrictions unconstitutional and unreasonable, and say they should only be applied to child molesters. The law forces many parolees to leave their homes, and additionally puts them with a “constant threat of ouster” looming over their new homes, if a new school or park is built nearby, according to Justice Raymond Ikola, who was part of the 3-0 ruling.