Brandenburg clarified what constituted a "
clear and present danger", the standard established by
Schenck v. United States (1919) and overruled by
Whitney v. California (1927), which had held that speech that merely advocated violence could be made illegal. Under the imminent lawless action test, speech is not protected by the
First Amendment if the speaker intends to incite a violation of the law that is both imminent and likely. While the precise meaning of "imminent" may be ambiguous in some cases, the Supreme Court provided later clarification in
Hess v. Indiana (1973), which found that Hess's words were protected under "his rights to
free speech", in part because his speech "amounted to nothing more than advocacy of illegal action at some indefinite future time," ==Quotation==