restrictions on speech on government property:  traditional public fora, designated public fora, and nonpublic fora.  Traditional public fora include sidewalks, squares, and public parks:  [S]treets and parks . . . have immemorially been held in trust for the use of the public and, time out of mind, have been used for purposes of assembly, communicating thoughts between citizens, and discussing public questions.  Such use of the streets and public places has, from ancient times, been a part of the privileges, immunities, rights, and liberties of citizens.

Hague, 307 U.S. at 515.  “In these quintessential public forums, . . . [f]or the State to enforce a content-based exclusion it must show that its regulation is necessary to serve a compelling state interest and that it is narrowly drawn to achieve that end.”  Perry Educ.  Ass’n v.  Perry Local Educs.  Ass’n, 460 U.S. 37, 45 (1983); see also Int’l Soc’y for Krishna Consciousness, 505 U.S. at 678 ("[R]egulation of speech on government property that has traditionally been available for public expression is subject to the highest scrutiny."); Frisby, 487 U.S. at 480 ("[W]e have repeatedly referred to public streets as the archetype of a traditional public forum.").  A second category of fora, known as designated (or limited) public fora, “consists of public property which the State has opened for use by the public as a place for expressive activity.”  Perry, 460 U.S. at 46.  Whereas any content-based restriction on the use of traditional public fora is subject to strict scrutiny, the state is generally permitted, as long as it does not discriminate on the basis of viewpoint, to limit a designated public forum to certain speakers or the discussion of certain subjects.  See Perry, 460 U.S. at 45 n.7.  Once it has defined the limits of a designated public forum, however, “[r]egulation of such property is subject to the same limitations as that governing a traditional public forum.”  Int’l Soc’y for Krishna Consciousness, 505 U.S. at 678.  Examples of designated fora include university meeting facilities, see Widmar v.  Vincent, 454 U.S. 263 (1981), school board meetings, see City of Madison Joint School Dist. v.  Wisc.  Employment Relations Comm’n, 429 U.S. 167 (1976), and municipal theaters, see Southeastern Promotions, Ltd. v.  Conrad, 420 U.S. 546 (1975).

The third category, nonpublic fora, consists of all remaining public property.  “Limitations on expressive activity conducted on this last category of property must survive only a much more limited review.  The challenged regulation need only be reasonable, as long as the regulation is not an effort to suppress the speaker’s activity due to disagreement with the speaker’s view.”  Int’l Soc’y for Krishna Consciousness, 505 U.S. at 679. 2.  Contours of the Relevant Forum:  the Library’s Collection as a Whole or the Provision of Internet Access?