use of a technology protection measure required by CIPA is not narrowly tailored to the government’s legitimate interest in preventing the dissemination of visual depictions that are obscene, child pornography, or in the case of minors, harmful to minors.  For the same reason that a public library’s use of software filters is not narrowly tailored to further the library’s interest in preventing its computers from being used to disseminate visual depictions that are obscene, child pornography, and harmful to minors, a public library’s use of software filters is not narrowly tailored to further the library’s interest in protecting patrons from being unwillingly exposed to offensive, sexually explicit material.  As discussed in our findings of fact, the filters required by CIPA block substantial numbers of Web sites that even the most puritanical public library patron would not find offensive, such as http://federo.com, a Web site that promotes federalism in Uganda, which N2H2 blocked as “Adults Only, Pornography,” and http://www.vvm.com/~bond/home.htm, a site for aspiring dentists, which was blocked by Cyberpatrol as “Adult/Sexually Explicit.”  We list many more such examples in our findings of fact, see supra, and find that such erroneously blocked sites number in at least the thousands.

Although we have found large amounts of overblocking, even if only a small percentage of sites blocked are erroneously blocked, either with respect to the state’s interest in preventing adults from viewing material that is obscene or child pornography and in preventing minors from viewing material that is harmful to minors, or with respect to the state’s interest in preventing library patrons generally from being unwillingly exposed to offensive, sexually explicit material, this imprecision is fatal under the First Amendment.  Cf.  Reno, 521 U.S. at 874 ("[T]he CDA lacks the precision that the First Amendment requires when a statute regulates the content of speech."); League of Women Voters, 468 U.S. at 398 ("[E]ven if some of the hazards at which [the challenged provision] was aimed are sufficiently substantial, the restriction is not crafted with sufficient precision to remedy those dangers that may exist to justify the significant abridgement of speech worked by the provision’s broad ban . . . .").

While the First Amendment does not demand perfection when the government restricts speech in order to advance a compelling interest, the substantial amounts of erroneous blocking inherent in the technology protection measures mandated by CIPA are more than simply de minimis instances of human error.  “The line between speech unconditionally guaranteed and speech which may legitimately be regulated, suppressed, or punished is finely drawn.  Error in marking that line exacts an extraordinary cost.”  Playboy, 529 U.S. at 817 (internal quotation marks and citation omitted).  Indeed, “precision of regulation must be the touchstone in an area so