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 closely touching our most precious
freedoms." Keyishian v. Bd. of Regents of the Univ. of the State
of N.Y., 385 U.S. 589, 603 (1967) (internal quotation marks and
citation omitted); see also Bantam Books, Inc. v. Sullivan, 372
U.S. 58, 66 (1963) ("The separation of legitimate from
illegitimate speech calls for sensitive tools.") (internal
quotation marks and citation omitted). Where the government
draws content-based restrictions on speech in order to advance a
compelling government interest, the First Amendment demands the
precision of a scalpel, not a sledgehammer. We believe that a
public library's use of the technology protection measures
mandated by CIPA is not narrowly tailored to further the
governmental interests at stake.
Although the strength of different libraries' interests in
blocking certain forms of speech may vary from library to
library, depending on the frequency and severity of problems