WASHINGTON - Taking up Congress' efforts to protect children from indecent material on the Internet, the Supreme Court announced yesterday that it would decide the constitutionality of a federal law that requires public libraries to use filtering software on computers used by the public.

A trial court struck down the law earlier this year, ruling that the filters wrongly blocked thousands of Web pages containing speech Congress never intended to regulate, including sites on politics, religion, women's health issues and sports. As a result, the court ruled, the law violates the First Amendment rights of millions of people who use the Internet at public libraries.

The Justice Department asked the justices to review that decision, arguing that it frustrates efforts by Congress to keep "the enormous amount of illegal and harmful pornography on the Internet" out of public libraries while ensuring that patrons still have Internet access.

Also yesterday, the court said it would hear arguments early next year on whether the city of Chicago is entitled to records on the sale or transfer of firearms used in criminal activity. The city was seeking the information to bolster its civil lawsuit against the firearms industry, but the Bureau of Alcohol Tobacco and Firearms declined to turn over the pertinent data.

"At bottom, it's a case about whether people are entitled to know what the federal government is doing to combat illegal drug trafficking and reduce violence," said Matt Nosanchuk, litigation director of the Violence Policy Center.

In its lawsuit against the gun industry, Chicago maintains that certain manufacturers, dealers and distributors have created a public nuisance by intentionally marketing handguns to residents in the city, where most of the firearms are illegal. It is seeking to recover the costs of police, medical and other services it incurs because of the illegal guns in the city.

To get information about how guns are distributed, the city wanted records the ATF compiles on the movement of guns used in criminal activity as well as information on gun sales. When the ATF declined to disclose significant information, including names and addresses, the city sued under the federal Freedom of Information Act.

A Chicago-based federal appeals court ruled earlier this year that the bureau could not withhold the requested information, saying nothing in the Freedom of Information Act warranted the ATF's declining to release the records.

The Justice Department argued in court papers that disclosing the sales information would interfere with law-enforcement proceedings and "significantly intrude upon the privacy of hundreds of thousands of individuals."

Jan Crawford Greenburg writes for the Chicago Tribune, a Tribune Publishing newspaper.