SACRAMENTO (CBS / AP) — A federal judge has blocked part of a voter-approved ballot initiative related to human trafficking.

The decision temporarily halts a provision of Proposition 35 that requires registered sex offenders to give authorities a list of their Internet identifiers. The initiative, passed Tuesday with 81 percent support, toughens penalties on those convicted of human trafficking.

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The American Civil Liberties Union of Northern California and the Electronic Frontier Foundation sued in U.S. District Court in San Francisco on behalf of sex offenders, saying the requirement restricts their First Amendment right to free speech.

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U.S. District Judge Thelton Henderson issued a temporary restraining order until a full hearing Nov. 20. He noted in the four-page order, issued Wednesday, that the state would not be able to enforce the provision until next spring.

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