Under what circumstances can constitutional rights be restricted?

The correct answer highlights the specific conditions under which constitutional rights, specifically First Amendment rights such as free speech, can be lawfully restricted. The presence of obscenity, defamation, and incitement represents established legal standards where speech may be curtailed because it poses identifiable harm to others or societal interests.

Obscenity is evaluated based on community standards and lacks serious literary, artistic, political, or scientific value, thereby justifying restrictions to protect societal morals. Defamation involves false statements that damage a person's reputation, which can lead to legal consequences and thus is regulated to protect individuals from false harm. Incitement refers to speech that provokes immediate violence or illegal action, which is not protected because it poses a direct threat to public order and safety.

Understanding that restrictions are applied in these scenarios illustrates how balancing individual rights with the need for community protection can sometimes necessitate limitations on freedom of expression.