What are the problems with market censorship or any kind of censorship in a democracy?

four sitting presidents have been assassinated while in office but the first was abraham lincoln,

the four most common systems of greek government were: democracy - rule by the people (male citizens). monarchy - rule by an individual who had inherited his role. oligarchy - rule by a select group of individuals.

hmm.. that's be opened free elementary school for young boys who showed artistic potential. closed rome to outsiders to protect its unique style and methods of producing art. and employed scribes to copy latin and greek texts.