In the early 20th century, incitement was determined by the "clear and present danger" standard established in Schenck v. United States (1919), in which Justice Oliver Wendell Holmes Jr. observed: “The question in every case is whether the words used are used in such circumstances and are of such a nature as to create a clear and present danger that they will bring about the substantive evils that Congress has a right to prevent.”[4] In Brandenburg v. Ohio (1969), this was narrowed to an "imminent lawless action" standard, with the Supreme Court unanimously reversing the conviction of a Ku Klux Klan group for "advocating ... violence ... as a means of accomplishing political reform" because their statements at a rally did not express an immediate, or imminent intent, to do violence.[5] This decision overruled Schenck v. United States (1919), which held that a "clear and present danger" could justify a law limiting speech. The primary distinction is that the latter test does not criminalize "mere advocacy".[6]