It is back to the federal courthouse in Philadelphia for attackers and defenders of the Child Online Protection Act, the law Congress passed last year to make the Internet safe for minors. \n In November, U.S. District Judge Lowell A. Reed blocked enforcement of the law until there was time for both sides to muster preliminary arguments. His temporary order is to last no longer than Feb. 1. \n Beginning Wednesday (Jan. 20), Judge Reed will hear three days' worth of arguments. At some point afterward--but before Feb. 1--he will rule on whether his temporary order should be turned into a preliminary injunction, a more permanent delay. \n The law, if it takes effect, will require commercial Web sites to require proof of age before Internet users are allowed to see any material that may be harmful to minors. The proof could take the form of a credit card number or some access code or age verification service. Each violation of the law would be punishable by up to six months in jail and a fine of up to $50,000. \n Those in favor of the law call it a reasonable way to keep kids away from Internet porn. They point out that, unlike the Communications Decency Act of 1996, the heart of which was declared by the U.S. Supreme Court to be an unconstitutional intrusion on First Amendment rights, the new law applies only to commercial Web sites. \n Donna Rice Hughes calls it a "brown paper wrapper," a reference to the material placed over adult magazines to keep them from the eyes of children. Hughes, who represents a group supporting the law, is best known as the woman whose frolicking with Colorado Sen. Gary Hart cost him his bid for the presidency in 1987. \n Leading the courtroom charge against the law is the American Civil Liberties Union. Stefan Presser, legal director of the ACLU of Pennsylvania, said if the law is upheld, it will transform the Internet into a tame and meaningless way of communicating things that are fit for a 6-year-old. The ACLU says the law violates free speech rights and could be used to prosecute gays, AIDS activists or even doctors distributing gynecological information. \n Friend-of-the-court briefs have been filed against the law by more than 20 organizations that represent publishers, journalists, Internet service providers and the technology industry. Some of the briefs argue that filtering technology is a much more effective and less onerous way of accomplishing the same objective.