experienced by each particular library, we conclude, based on our
findings of fact, that any public library's use of a filtering
product mandated by CIPA will necessarily fail to be narrowly
tailored to address the library's legitimate interests. Because
it is impossible for a public library to comply with CIPA without
blocking substantial amounts of speech whose suppression serves
no legitimate state interest, we therefore hold that CIPA is
facially invalid, even under the more stringent standard of
facial invalidity urged on us by the government, which would
require upholding CIPA if it is possible for just a single
library to comply with CIPA's conditions without violating the
First Amendment. See supra Part III.
3. Less Restrictive Alternatives


The constitutional infirmity of a public library's use of
software filters is evidenced not only by the absence of narrow
tailoring, but also by the existence of less restrictive
alternatives that further the government's legitimate interests.
See Playboy, 529 U.S. at 813 ("If a less restrictive alternative
would serve the Government's purpose, the legislature must use
that alternative."); Sable, 492 U.S. at 126 ("The Government may
. . . regulate the content of constitutionally protected speech
in order to promote a compelling interest if it chooses the least
restrictive means to further the articulated interest.").
As is the case with the narrow tailoring requirement, the
government bears the burden of proof in showing the
ineffectiveness of less restrictive alternatives. "When a
plausible, less restrictive alternative is offered to a content-
based speech restriction, it is the Government's obligation to