Megan's Law is the name for a federal law, and informal name for subsequent state laws, in the United States requiring law enforcement authorities to make information available to the public regarding registered sex offenders. Laws were created in response to the murder of Megan Kanka. Federal Megan's Law was enacted as a subsection of the Jacob Wetterling Crimes Against Children and Sexually Violent Offender Registration Act of 1994, which merely required sex offenders to register with local law enforcement. Since only few states required registration prior to Megan's death, the state level legislation to bring states in compliance —with both the registration requirement of Jacob Wetterling Act and community notification required by federal Megan's Law— were crafted simultaneously and are often referred as "Megan's Laws" of individual states. Thus, federal Megan's Law refers to community notification (making registry information public), whereas state level "Megan's Law" may refer to both sex offender registration and community notification.
In 1997, the ACLU and several other groups, argued that the law was unconstitutional as it was paramount to an ex post facto punishment, among other constitutional arguments. The case was assigned to then Federal District Court Judge, Denny Chin, who quashed the law based on that main argument. Assemblyman Daniel Feldman, who drafted the bill which became law in New York, in 1997. Chin, and 2010 was nominated and confirmed by the Senate to be promoted to the Second Circuit Court of Appeals. A staffer for Feldman, Michael Prete, who would have Chin as his legal writing Professor at Fordham Law School in 1999, first dealt with Chin, two years earlier in an adversarial relationship as he was assisting Feldman in trying to prove to Chin, how the law was Constitutional. Two years later, it was quite surprising for Prete to see Chin as his professor. In 1997 the case was appealed to the Second Circuit Court of Appeals, and reversed Chin's ruling, 3-0, and the law became Constitutional again. And as a result, within the next 2–3 years, all 50 states had their own version of Megan's law on the books.