The Bush Administration urged the Supreme Court to protect the nation's children by upholding a U.S. law that would shut down the $2-billion "dial-a-porn" industry. Congress was justified when it passed a law last year banning all sexually explicit telephone dial-up message services to "protect children from hearing patently offensive speech," Justice Department lawyer Richard Taranto said. But Harvard law professor Laurence H. Tribe, representing a major purveyor of dial-a-porn services, said Congress went too far. Saying attempts by children to reach the 976 numbers used by dial-a-porn companies can be frustrated by technological safeguards, Tribe said: "Their availability makes this flat ban illegitimate." The 976 exchanges also are used for other, non-controversial types of messages, such as sport scores, time checks and weather reports.