The United States Supreme Court is considering whether it is unconstitutional for libraries to block access to internet porn sites.
By Steve Schifferes
BBC News Online in Washington
Libraries must block access to child pornography
On Wednesday the court met to hear arguments in a case brought by the American Libraries Association, which is arguing that a new Federal law insisting that every library install filters against obscene material on its computers used to access the internet violates the First Amendment, which protects free speech.
Under the Children's Internet Protection Act, libraries that receive federal subsidies must use software that screens out obscenity, child pornography, and sexually explicit material deemed harmful to minors.
The case could have wide-ranging implications for the future of the internet, which is already facing calls for further restrictions on its content from legislators throughout the United States.
The First Amendment does not require libraries to sponsor the
viewing of pornography
Solicitor General Ted Olson
And the argument goes to the heart of the cultural debate which is now proving more powerful than economic interests in creating political divisions among the US electorate.
Arguing in favour of the law on behalf of the Bush administration, Solicitor General Ted Olson said that "the First Amendment does not require libraries to sponsor the viewing of pornography."
But Paul Smith, representing librarians, said that "the federal government has no business using its spending power to... push librarians away from their professional judgment" as to what material to supply to the public.
A key part of the case revolves around the use of commercially available porn filters to sort out content which the public then cannot access from libraries.
Civil rights groups argue that the filters are inaccurate, missing some sites they are intended to block and screening out others that the public has a right to see.
Ted Olson told the court that only 0.1% of internet sites would be incorrectly blocked by the filters, and argued that the law allows adults to request the libraries to remove the filters if they need access for research purposes.
But the librarians' attorney said that some filters got 25% of their sites wrongly blocked.
Supreme Court divided
The questioning by the judges revealed the sharp divisions between them that are increasingly obvious on the court.
The librarians' key argument is that the internet is a specially protected place - a public forum - where free speech must be respected, just as if it were a physical meeting place.
"The library as a whole is not a public forum, as material is selected, but the internet is," Mr Smith said. "It is the most
pure form of public forum you can imagine."
Several justices expressed scepticism about this view, including Justice Antonin Scalia, who said that librarians commonly block many internet functions, such as chat rooms and e-mail.
And Justice Sandra Day O'Connor was worried that if public library internet access was protected speech, then how could schools regulate the use of the internet in school libraries.
But Justice Kennedy said that he was concerned that librarians were not able to access information about the content of sites they were blocking, in contrast to their ability to make informed decisions about what books to buy.
Another argument discussed by the court was whether free speech would be served if people had the right to request the filters to be turned off - and whether the library had to grant that request.
"What is the great burden on speech?" Justice Stephen Breyer asked. "I grew up in a world where they kept certain materials in a separate place in the library and you had to go and ask for them."
"You still have the problem of going up to the librarian and saying, 'Please turn off the smut filter,'" Mr Smith replied.
More than 14 million Americans use public library computers to do research and send and receive e-mail, especially low-income household who have no other internet access.
The court had previously blocked two other attempts by Congress to regulate child pornography on the internet.
The case will be decided by the end of the court's current term in July.