When the United States Department of Justice used the authority of the USA PATRIOT Act of 2001 to conduct searches of what once were confidential library databases, Krug raised a public outcry against this activity by the government.

Her efforts led to a partial victory for anti-censorship campaigners; the Supreme Court of the United States ruled that the law was constitutional, but that filtering software on computers in public libraries could be turned off if so requested by an adult guardian.

Krug warned that the filters used to censor Internet pornography from children were not perfect and risked blocking educational information about social matters, sexuality, and healthcare.

[3] As director of the OIF, Krug organized publication of a newsletter which recounted instances of censorship in the U.S. and suggested ways to deal with these attempts to limit free speech.

[1][13] She coordinated opposition to the Communications Decency Act of 1996, which was the first attempt by the United States Congress to introduce a form of censorship of speech on the Internet.

[14] When the United States Department of Justice used the authority of the USA PATRIOT Act of 2001 to conduct searches of once-confidential library databases, Krug raised a public outcry against this government action.

[2] Her efforts led to a partial victory for the Act's opponents; the Supreme Court of the United States ruled that the law was constitutional, but that internet filtering software on computers in public libraries could be turned off if so requested by an adult guardian.

[2] She said that filters used to censor Internet pornography from children were not perfect and risked blocking educational information about social matters, sexuality, and healthcare.

[20] The Judith F. Krug Memorial Fund was founded by the American Library Association to ensure that Banned Books Week would remain active after her death.