At press time, three federal judges had the task of deciding whether preventing or delaying adults’ access to some constitutionally protected speech is an acceptable side effect of keeping online pornography away from children.

Closing arguments before the Third U.S. Circuit Court of Appeals in Philadelphia April 4 marked the end of nearly two weeks of testimony over the Children’s Internet Protection Act, or CIPA, a law requiring schools and libraries receiving federal eRate discounts to install filtering software to prevent access to online smut. Under the law, libraries that don’t install such software risk losing their funding.

The lawsuit applies only to libraries, not schools. But legal experts say a ruling for the plaintiffs could open the door to similar legal challenges in school systems.

Attorneys for the plaintiffs—which include the American Library Association, a coalition of various public libraries, and library patrons—said the evidence they presented shows the law is unenforceable, censors speech to adults as well as children, is overly vague and broad, and denies poor people without home computers the same full access to information as their wealthy neighbors.

“Ninety-three percent of the libraries in this country have chosen not to use blocking software on their computers. That’s got to say something,” said Chris Hansen, an attorney for the American Civil Liberties Union.

The government maintains that internet pornography is so pervasive that protections need to be in place to keep it away from the eyes of youngsters, and that the law simply calls for libraries to use the same kind of care in selecting online content as they do for books and magazines.

Justice Department attorney Rupa Bhattacharyya said filters aren’t perfect but are efficient enough to support the mandates outlined in the statute, and added that CIPA does not discriminate based on viewpoints, only content.

The panel of judges was expected to rule on the case by early May to give libraries time to comply if the law is upheld and goes into effect as scheduled July 1. Any appeal of the panel’s decision would go directly to the U.S. Supreme Court.