Retroactive enforcement of Tennessee’s sex offender registry law is being challenged in a federal court lawsuit that mimics a separate, successful appeal that led to the nullification of retroactive laws in Michigan. The case, filed Tuesday in U.S. District Court in Nashville, argues that Tennessee’s registration laws are illegally applied retroactively. It notes that the laws and restrictions on those offenders have become significantly more burdensome since the laws were first enacted in 1994. The first registry law deemed the register of sex offenders confidential and only accessible by law enforcement. The General Assembly tweaked the law multiple times, and made registrants public, and then…