A federal judge said Thursday she plans to rule within a month on the constitutionality of an Indiana law that bans registered sex offenders from using social networking websites where they could prey on children.

The American Civil Liberties Union of Indiana is heading the class-action suit on behalf of a man who served three years for child exploitation, along with other sex offenders who are restricted by the ban even though they are no longer on probation. Federal judges have barred similar bans in Nebraska and Louisiana. Similar restrictions remain in effect in New York, Illinois and North Carolina.

In a one-hour hearing at U.S. District Court in Indianapolis, Judge Tanya Walton Pratt questioned attorneys about convicted sex offenders' civil rights and whether the state law is outdated in the age of Facebook, LinkedIn and dozens of other social networking sites.

ACLU attorney Ken Falk argued that even though the 2008 law is only intended to protect children from online sexual predators, it also prevents sex offenders from using social media for political, business and religious activity such as using Facebook to follow the pope or comment on newspaper websites, posting a profile on LinkedIn or following presidential candidates on Twitter.

Falk said the law violates the rights of communication, receiving information and association, all of which the U.S. Supreme Court has ruled are guaranteed by the First Amendment. He also argued that the ban was unnecessary because Indiana already has a law that makes it a crime to use the Internet to contact a child for the purposes of sexual gratification.

Indiana Deputy Attorney General David Arthur argued that the 2008 ban is limited only to social networking sites that allow access by children, and that Facebook, Twitter and similar sites aren't the only forms of communication.

"We still have television. We still have radios. And believe it or not, people still talk face-to-face," he said. Arthur also said the ban doesn't apply to email or Internet message boards.

Falk said social media are almost indispensable. "It's not enough to say that the plaintiffs can still write letters or go to meetings," he said. "These are not adequate alternatives for instant communication."

Courts have long allowed states to place restrictions on convicted sex offenders who have completed their sentences, controlling where many of them live and work and requiring them to register with police. But Falk told Pratt that the social networking ban was far broader, restricting a wide swatch of constitutionally protected activities.

Arthur compared the social networking ban to laws barring sex offenders from school property and other places frequented by kids. Only in this case, he said, the place is virtual.

Similar social networking bans have been struck down in two other states.

In February, U.S. District Judge Brian Jackson found that Louisiana's prohibition was too broad and "unreasonably restricts many ordinary activities that have become important to everyday life."

Louisiana lawmakers passed a new law this month that more narrowly defines which sites are prohibited. News and government sites, email services and online shopping are excluded from the new rules, as are photo-sharing and instant-messaging systems. The measure takes effect Aug. 1.

In Nebraska, a federal judge in 2009 blocked part of a law that included a social networking ban. A second legal challenge by an Omaha-area sex offender is set for trial in July.