I am unable to immediately find any case that overturns this decision. Law-Speaking types - a little help? I start this unit Monday and I know my students will be full of questions.
(Yes, Mods - I am asking for help with my homework.) 
One answer is that Pico was a 4-4 -1 decision with no majority rationale (and the fifth vote didn’t address the First Amendment issue). In essence, it can’t be overturned, but it didn’t create any binding rule.
what “book bans” are you talking about?
Do you mean they took them off the study curriculum for certain grades? That’s not banning, but it is commonly call banning. They didn’t ban Maus for example. It was still in the school library, They just took it off the reading list for younger kids.
That decision only applies to removing books from school libraries, which maybe kinda is a sorta ban.
Or do you mean owning or selling a copy is illegal, or mass book burnings?
From what I’ve read in the news - they are not censoring books, so much as the law is threatening anyone who provides children with books that could “lead them astray” (For various ambiguous definitions of “astray”). As a result, the assorted school divisions are doing the CYA thing and hiding books - much like Canadian stores have to hide their cigarette displays.
Whether threatening librarians about vaguely worded topics is equivalent to prior restraint and censorship, I guess that’s a topic for the Supreme Court to figure out.
That’s different than this vague Florida statute, which triggers self-censorship.
Canadian cigarette vendors are required by law not to display them in areas where 18 and under are present. No CYA involved; it’s what the law requires.
First Amendment lawsuits have started. Island Trees vs Pico isn’t mentioned in the articles but Board of Education vs Pico is mentioned in the lawsuit.
Escambia County in northwest Florida has removed or restricted at least 16 books from public school libraries and classrooms. They range from a Nobel Prize winner’s first novel to a popular coming-of-age bestseller that came out in the 1990s.
A Florida county school district is allegedly violating the First Amendment by its removal of books discussing race, racism and LGBTQ+ identities, according to a federal lawsuit filed Wednesday by Penguin Random House, PEN America, authors and parents.
The lawsuit claims that the school district ordered the removal of books against the recommendations of its own experts, with the banned books including “The Bluest Eye” by Toni Morrison, “The Nowhere Girls” by Amy Reed and “Lucky” by Alice Sebold.
I guess that goes to the heart of what “free speech” means. Fortunately. Canada does not have a First Amendment.
I wonder how this works out woth the school boards, if they are essentially in the middle - they have to obey Florida law and the First Amendment, which may or may not collide. Protecting children (as in covering cigarette ads, or restricting access to quasi-pornographic materials) may or may not be a legitimate exception to the first amendment, depending on how inappropriate the content is, and who gets to decide what is inappropriate. After all, a story like To Kill A Mockingbird may give children a warped view of life. (Hint-sarcasm)