from accessing obscenity and child pornography than software
filters. As detailed in our findings of fact, the underblocking
that results from the size, rate of change, and rate of growth of
the Internet significantly impairs the software filters from
preventing patrons from accessing obscenity and child
pornography. Unless software filters are themselves perfectly
effective at preventing patrons from accessing obscenity and
child pornography, "[i]t is no response that [a less restrictive
alternative] . . . may not go perfectly every time." Playboy,
529 U.S. at 824; cf. Denver Area Educ. Telecomm. Consortium, Inc.
v. FCC, 518 U.S. 727, 759 (1996) ("No provision . . . short of an
absolute ban, can offer certain protection against assault by a
determined child.").


The government has not offered any data comparing the
frequency with which obscenity and child pornography is accessed
at libraries that enforce their Internet use policies through
software filters with the frequency with which obscenity and
child pornography is accessed at public libraries that enforce
their Internet use policies through methods other than software
filters. Although the government's library witnesses offered
anecdotal accounts of a reduction in the use of library computers
to access sexually explicit speech when filtering software was
mandated, these anecdotal accounts are not a substitute for more
robust analyses comparing the use of library computers to access
child pornography and material that meets the legal definition of
obscenity in libraries that use blocking software and in
libraries that use alternative methods. Cf. Playboy, 529 U.S.
at 822 ("[T]he Government must present more than anecdote and