In constitutional law, the principle that the government, notwithstanding the First Amendment to the United States Constitution, may restrict, prohibit, or punish speech or the printing and distribution of words if it is necessary to prevent a clear and present danger of an event that the government has a right to prevent. For example, the government may prohibit a person from falsely crying out “Fire!” in a crowded room in order to prevent panic and injury. This principle was first articulated in the United States Supreme Court case of Schenck v. United States (1919).