In U.S. constitutional law, a facial challenge is a challenge to a statute in which the plaintiff alleges that the legislation is always unconstitutional, and therefore void. It is contrasted with an as-applied challenge, which alleges that a particular application of a statute is unconstitutional. In First Amendment cases, another type of facial challenge is enunciated in the overbreadth doctrine. If a statute reaches to include substantially protected conduct and speech in relation to the legitimate reach of the statute, then it is overbroad and thus void on its face.