Freedom of speech in the United States is protected by the First Amendment to the United States Constitution and by many state constitutions and state and federal laws.
In Reno v. ACLU[i], the U.S. Supreme Court extended the full protection of the First Amendment to the Internet and struck down portions of the 1996 Communications Decency Act. The court’s decision extended the same Constitutional protections given to books, magazines, films, and spoken expression to materials published on the Internet. Congress tried a second time to regulate the content of the Internet with the Child Online Protection Act (COPA). The Court again ruled that any limitations on the internet were unconstitutional in American Civil Liberties Union v. Ashcroft.[ii]
In United States v. American Library Association, the Supreme Court ruled that Congress has the authority to require public schools and libraries receiving e-rate discounts to install filters as a condition of receiving federal funding. The court was of the opinion that any First Amendment concerns were addressed by the provisions in the Children’s Internet Protection Act that permit adults to ask librarians to disable the filters or unblock individual sites.
[i] 521 U.S. 844 (1997)
[ii] 535 U.S. 564 (2002)