I never heard of the Smith Act until you asked the above question, so, thank you Patriot. A conspiracy can exist even though the activities of the defendants do not culminate in an attempt to overthrow the government by force and violence. A conspiracy to advocate overthrow of the government by force or violence, as distinguished from the advocacy itself, can be constitutionally restrained even though it consists of mere preparation because the existence of the conspiracy creates the peril. https://law.jrank.org/pages/10334/Smith-Act.html