When is a law unconstitutionally overbroad?

Hypo 1: The state of Hypofornia is worried about growing political tensions and threats on the life of political leaders. To combat this threat, it passes a law making it illegal to "say anything offensive about the Governor." Bob writes an opinion piece harshly criticizing the Governor's tax policies, arguing that they unfairly burden the middle class. The Governor orders Bob's prosecution under the new law. Result: The law is unconstitutionally overbroad. While it may validly prohibit certain true threats or incitement against the Governor, it sweeps in a substantial amount of protected political speech, like Bob's critique of the Governor's policies. The court would likely strike down the law as facially invalid, precluding Bob's prosecution.

Hypo 2: Concerned about cyberbullying, the state of New Hypoland enacts a law prohibiting "any electronic communication intended to coerce, intimidate, harass, or cause substantial emotional distress to a person." Sam sends his ex-girlfriend Amy a series of messages threatening to distribute nude photos of her unless she agrees to get back together with him. Amy reports Sam to the police. Result: While intended to address legitimate harms, this law could also criminalize protected speech that is merely unpleasant or insulting without rising to the level of true threats, criminal coercion, or intentional infliction of emotional distress. Since it likely regulates substantially more speech than the narrow categories that can be validly prohibited, a court would probably find it unconstitutionally overbroad and unenforceable against anyone, including Sam — even though what Sam did was terrible.

Hypo 3: Hypofornia makes it a crime to "wear any mask or disguise with the intent to intimidate any person or group of persons." Bob, a member of a white supremacist organization, burns a cross on Sam's lawn while wearing a mask as part of a campaign to drive Sam out of the neighborhood. Result: The law aims to prohibit constitutionally unprotected true threats and intimidation. Unlike the previous examples, it does not reach a substantial amount of protected First Amendment activity in relation to its plainly legitimate sweep. Any impact on protected symbolic speech is minimal. The law would likely be upheld, and Bob could be validly prosecuted under it.

Hypo 4: New Hypoland adopts a statute prohibiting anyone from making statements that "promote the illegal use of controlled substances." Bob, a harm reduction advocate, creates a website with resources on how to use drugs more safely to reduce overdoses and disease transmission. Result: This law is likely unconstitutionally overbroad. While the government has more leeway to regulate speech concerning illegal drugs, this prohibition could encompass a wide range of protected speech, such as political advocacy for reforming drug laws, as well as legitimate public health information like Bob's harm reduction materials. Since it substantially infringes protected speech in relation to its valid applications, it would probably be struck down.