History
The Overbreadth Doctrine in First Amendment Jurisprudence
Quick fact
In the 1973 case Broadrick v. Oklahoma, the U.S. Supreme Court ruled that a law can be struck down as overbroad only if the overbreadth is 'substantial' relative to the law's plainly legitimate sweep—meaning a law that is overbroad in trivial ways usually survives.
Why this is interesting
Imagine a law that punishes anyone who 'annoyingly speaks' in public. Even if you're on your best behavior, you might stay silent—because you're not sure what 'annoying' means. Courts worry about exactly that, and they have a special tool to stop such laws.