What are content-based restrictions, and which level of scrutiny is applied?

Hypo 1: The state of Hypofornia passes a law banning any public protests or rallies criticizing the governor's economic policies, claiming they could lead to violence. Sam opposes the governor's recent tax plan and wants to organize a peaceful march, but is told by police that his rally would be illegal under the new law. Result: This law would almost certainly be struck down as an unconstitutional content-based restriction on speech. The ban is based entirely on the topic (criticism of the governor's economic policies) and viewpoint (opposition to those policies) of the speech. While preventing violence is a compelling state interest, banning all critical speech on this topic is not narrowly tailored to that interest, especially since Sam is planning a peaceful rally. The law essentially censors an entire political viewpoint, which violates the core of the First Amendment.

Hypo 2: Hypofornia enacts a statute prohibiting any speech on state college campuses that "defames or insults" any racial or ethnic group. A student group led by Sam wants to bring a controversial conservative speaker to campus who has made statements harshly criticizing illegal immigration and claiming that Mexican immigrants are "invading" the country. The college denies their request, saying the speech would violate the defamation law. Result: This law and the college's actions would violate the First Amendment. The restriction is clearly content-based, as it bans speech related to race and ethnicity that is deemed offensive or insulting. Even if avoiding racial discord is a compelling interest, this blanket ban on insults and "defamation" (which implies false statements, not just offensive ones) is far too broad. It would censor huge amounts of speech, including core political speech on issues like immigration, and is not the least restrictive means to pursue that interest. Offensive speech is still constitutionally protected.

Hypo 3: The city of Hypovia passes an ordinance banning public nudity citywide. Bob wants to hold a nude protest against the mayor but is told he will be arrested if he does so. Result: This law would likely be upheld as constitutional. While it does restrict expressive conduct (the nude protest), the restriction is not based on the content of that expression. The ban on nudity applies regardless of the subject matter or viewpoint of the proposed nude speech. Public nudity bans are justifiable under a lower level of scrutiny as a content-neutral regulation of the time, place and manner of speech. The city has a substantial interest in public order, morality and cleanliness that justifies a ban on nudity, and the law still leaves ample alternative channels for Bob to express his criticisms of the mayor.

Hypo 4: New Hypoland enacts a law banning the sale of any video games containing graphic violence against human characters. Game stores owned by Bob and Sam challenge the law as violating their free speech rights. Result: This law raises serious First Amendment issues as a content-based restriction on protected speech (video games have been held to be speech by the Supreme Court). The state would have to prove a compelling interest (like preventing real-world violence) that justifies singling out video game violence compared to violence in other media. And the law would have to be proven to actually help achieve that interest and be the least restrictive means to do so. Given the lack of clear evidence linking video games to real violence, a court would likely find this an overinclusive law that unconstitutionally restricts speech based on its violent content.