Maine’s highest court has upheld the state’s sex offender registration law in a narrow 4-3 decision, saying it does not violate the rights of people convicted of sex crimes before 1999, when the law was retroactively applied to include them. The majority opinion released Tuesday said Maine’s law requiring offenders to register and have their names posted online is “non-punitive” and serves the legitimate governmental goal of protecting public safety. Lawyers for the 15 plaintiffs, referred to as John Doe in court documents, argued that registration is an unconstitutional punishment. They petitioned to have their names removed, in part because they had already paid their debts to society. Jim Mitchell, a plaintiffs’ attorney, says the decision is disappointing but is unlikely to appeal in federal court.