Passed in 2000, the Children's Internet Protection Act (CIPA) mandates Internet filtering for all public schools and libraries. Challenges to the law have been raised on constitutional grounds by free-speech advocates such as the American Library Association and the American Civil Liberties Union. After losing one such challenge in district court, the federal government appealed to the U.S. Supreme Court, where the law was upheld in June 2003, though not without possible future concerns. CIPA has profound implications for K-12 school leaders and technology specialists, and a history of the law reveals much about its origins and purpose.