A federal judge has ruled that parts of Tennessee’s sex offender registration act should not be applied retroactively to two offenders who sued over the law. Monday’s ruling in the U.S. District Court for the Middle District of Tennessee was narrowly written to apply only to the two plaintiffs — identified as John Doe #1 and John Doe #2. But it could open the door to more lawsuits and a broader ruling in the future. The judge ruled that parts of the law violate a clause of the U.S. Constitution that prevents people from being punished by a law passed after their crime was committed.