On Friday, the Supreme Court decided United States v. Hansen. In this case, the defendant promised aliens that they could obtain citizenship through "adult adoption." In the process, the defendant induced the aliens to stay in the country illegally. Hansen was convicted of violating a federal statute that forbids "encourag[ing] or induc[ing] an alien to come to, enter, or reside in the United States, knowing or in reckless disregard of the fact that such [activity] is or will be in violation of law." On appeal, Hansen argued that this statute violated the Free Speech Clause of the First Amendment. To be sure, Hansen's own conduct was not protected speech. Rather, Hansen asserted that the entire statute was "invalid" under the so-called overbreadth doctrine.
Generally, a person only has "standing" to challenge a law when it violates that person's rights. However, an overbreadth challenge allows a person to assert that the government has violated the free speech rights of third parties who are not before the court. In other words, the overbreadth doctrine allows someone whose speech can be prohibited to assert that a statute is unconstitutional. This approach allows courts to vigorously scrutinize laws that may violate the freedom of speech — even for those people who might never be prosecuted for violating these laws.
This doctrine, which was developed by (you guessed it) the Warren Court, never quite fit into constitutional law. All the usual rules of standing are thrown out the window, and a defendant can be acquitted even if his own conduct is unprotected by the First Amendment. Civil rights litigants often rely on the overbreadth doctrine, which allows them to challenge statutes on their face, even if they are not subject to a present-day injury. The 3D-printed gun litigation, which I've been involved with for some time, has invoked the overbreadth doctrine.
