[1.] Next week, the entire en banc Fifth Circuit will be hearing Little v. Llano County, a case involving allegations of viewpoint-based book removals in a public library. As I've noted before, the Supreme Court has never resolved whether such removals are unconstitutional. Pico v. Bd. of Ed. (1982), which considered the matter as to public school libraries, split 4-4 on the subject, with the ninth Justice, Justice White, expressly declining to resolve the substantive question. (The Pico Justices generally agreed that schools could remove some material as age-inappropriate because of its vulgar or sexual content; the debate was about viewpoint-based removals.)
U.S. v. American Library Ass'n (2003), which dealt with the related question of Internet filtering in public libraries generally, was also a splintered decision, and didn't resolve the broader question, either. A 1995 Fifth Circuit panel decision had generally precluded such viewpoint-based removals, but the Fifth Circuit en banc court will need to consider whether that decision should stand: Rehearing by the full en banc court is the normal way that federal appellate courts reconsider whether three-judge panel decisions should be overruled.
I'm not sure what the answer here should be. I tentatively think a public school is entitled to decide which viewpoints to promote through its own library: School authorities can decide that their library will be a place where they provide books they recommend as particularly interesting/useful/enlightening/etc., essentially as supplements to the school curriculum (over which the school has broad authority). The process of selecting library books is part of the government's own judgment about what views it wishes to promote. And the ability to reconsider selection decisions—including in response to pressure from the public, which is to say from the ultimate governors of the public schools—should go with the ability to make those decisions in the first place. To be sure, some such decisions may be foolish or narrow-minded, but they're not unconstitutional.