[JURIST] US District Judge Lawrence Karlton [official profile] ruled in California Friday that the state's Proposition 83 [text, PDF; JURIST news archive] could not be applied retroactively to sex offenders released before its approval because there was nothing in the measure that indicated that intent. The measure prohibits registered sex offenders [JURIST news archive] from "residing within 2,000 feet of any public or private school or park where children regularly gather."

Proposition 83 was approved last November by 70 percent of California voters [results, CA Secretary of State; Yes on 83 advocacy website]. It faced an immediate legal challenge [JURIST report] from unidentified registered sex offenders, and a federal judge issued a temporary restraining order [JURIST report] to prevent the enforcement of the law's residency requirements pending a ruling on the merits. Critics have argued that the bill would create enforcement problems [CACJ statement, PDF] and encourage registered sex offenders not to report their addresses. AP has more.