In analyzing the constitutionality of a public library’s use of Internet filtering software, we must first identify the appropriate level of scrutiny to apply to this restriction on patrons’ access to speech.  While plaintiffs argue that a public library’s use of such filters is subject to strict scrutiny, the government maintains that the applicable standard is rational basis review.  If strict scrutiny applies, the government must show that the challenged restriction on speech is narrowly tailored to promote a compelling government interest and that no less restrictive alternative would further that interest.  United States v.  Playboy Entm’t Group, Inc., 529 U.S. 803, 813 (2000).  In contrast, under rational basis review, the challenged restriction need only be reasonable; the government interest that the restriction serves need not be compelling; the restriction need not be narrowly tailored to serve that interest; and the restriction “need not be the most reasonable or the only reasonable limitation.”  Cornelius v.  NAACP Legal Def. & Educ.  Fund, 473 U.S. 788, 808 (1985).

Software filters, by definition, block access to speech on the basis of its content, and content-based restrictions on speech are generally subject to strict scrutiny.  See Playboy, 529 U.S. at 813 ("[A] content-based speech restriction . . . can stand only if it satisfies strict scrutiny.").  Strict scrutiny does not necessarily apply to content-based restrictions on speech, however, where the restrictions apply only to speech on government property, such as public libraries. “[I]t is . . . well settled that the government need not permit all forms of speech on property that it owns and controls.”  Int’l Soc’y for Krishna Consciousness, Inc. v.  Lee, 505 U.S. 672, 678 (1992).  We perforce turn to a discussion of public forum doctrine. 1.  Overview of Public Forum Doctrine The government’s power to restrict speech on its own property is not unlimited.  Rather, under public forum doctrine, the extent to which the First Amendment permits the government to restrict speech on its own property depends on the character of the forum that the government has created.  See Cornelius v.  NAACP Legal Def. & Educ.  Fund, Inc., 473 U.S. 788 (1985).  Thus, the First Amendment affords greater deference to restrictions on speech in those areas considered less amenable to free expression, such as military bases, see Greer v.  Spock, 424 U.S. 828 (1976), jail grounds, see Adderley v.  Florida, 385 U.S. 39 (1966), or public airport terminals, see Int’l Soc’y for Krishna Consciousness, Inc. v.  Lee, 505 U.S. 672 (1992), than to restrictions on speech in state universities, see Rosenberger v.  Rector & Visitors of Univ. of Va., 515 U.S. 819 (1995), or streets, sidewalks and public parks, see Frisby v.  Schultz, 487 U.S. 474 (1988); Hague v.  CIO, 307 U.S. 496 (1939).  The Supreme Court has identified three types of fora for purposes of identifying the level of First Amendment scrutiny applicable to content-based