In Schenck v United States 1919, the US Supreme Court begat the expression "obvious risk" to cover "free discourse" cases that could sensibly bring about mischief or peril.
Charles Schenck and Elizabeth Baer were individuals from the Executive Committee of the Socialist Party in Philadelphia amid World War I. They printed pamphlets with the messages, "Don't submit to terrorizing", "Declare your rights", "On the off chance that you don't attest and bolster your rights, you are denying or stigmatize rights which it is the serious obligation of all subjects and inhabitants of the United States to hold." They were encouraging men to reject the draft.