infra

 at 58 74.  One failure of critical importance is that the automated systems that

filtering companies use to collect Web pages for classification are able to search only

text, not images.  This is crippling to filtering companies' ability to collect pages

containing  visual depictions  that are obscene, child pornography, or harmful to minors,

as CIPA requires.  As will appear, we find that it is currently impossible, given the

Internet's size, rate of growth, rate of change, and architecture, and given the state of the

art of automated classification systems, to develop a filter that neither underblocks nor

overblocks a substantial amount of speech.  

The government, while acknowledging that the filtering software is imperfect,

maintains that it is nonetheless quite effective, and that it successfully blocks the vast

majority of the Web pages that meet filtering companies' category definitions (e.g.,

pornography).  The government contends that no more is required.  In its view, so long as

the filtering software selected by the libraries screens out the bulk of the Web pages

proscribed by CIPA, the libraries have made a reasonable choice which suffices, under

the applicable legal principles, to pass constitutional muster in the context of a facial

challenge.  Central to the government's position is the analogy it advances between

Internet filtering and the initial decision of a library to determine which materials to

purchase for its print collection.  Public libraries have finite budgets and must make

choices as to whether to purchase, for example, books on gardening or books on golf. 

Such content based decisions, even the plaintiffs concede, are subject to rational basis

review and not a stricter form of First Amendment scrutiny.  In the government's view,

10