(WASHINGTON) -- Congress violated free-speech rights when it sought to protect children from sex-oriented cable channels like Playboy Television, the Supreme Court ruled today.

The 5-4 decision said Congress went too far when it required cable TV systems to restrict sex-oriented networks to overnight hours if they do not fully scramble their signal for nonsubscribers.

``If television broadcasts can expose children to the real risk of harmful exposure to indecent materials, even in their own home and without parental consent, there is a problem the government can address,'' Justice Anthony M. Kennedy wrote for the court. ``It must do so, however, in a way consistent with First Amendment principles.

``Here the government has not met the burden the First Amendment imposes,'' Kennedy said.

The justices upheld a lower court's conclusion that less restrictive alternatives are available to address the issue.