Free Speech
Protected by First Amendment
Opposite of free speech - Censorship
Government
NASCAR Banned display of the Confederate flag (美国南部邦联支持者 (Confederate))
What types of speech is the First Amendment designed to protect? Unpopular Speech!
Political Speech - Most Highly Protected
Personal Speech - Next Highly Protected
Commercial Speech - Least Protected
Such as: "Ｎow enriched with MZQ!" is not allowed.
Restriction to content subject to "Strict Scrutiny"
Exception to Free Speech
1. Obscene (adj. 淫秽的；猥亵的；可憎的) Speech (as opposed to "indecent" speech)
2. Actual Child Pornography
3. Certain Criminal Conduct that has a speech component
4. Speech presenting a "clear and present danger of great harm" - "imminent lawless action (the clear and present danger)"
5. Defamation (fake speech that harms someone‘s reputation)
6. Certain National Security issues
原文：https://www.cnblogs.com/JasperZhao/p/13096881.html