The Sedition Act allowed the government to fine or imprison someone based upon writings that have been against the government in a 'false, scandalous, and malicious' manner. Which is pretty broad. It also required that it be done with the intent of bringing the government into 'contempt or disrepute; or to excite against them ... the hatred of the ... people'.
It was intended as a war time act to protect the nation from internal sabotage but it was quickly used by the Federalists as a political weapon in an election year. Four of the five most prominent Republican newspapers were shut down and their main agitators tried and imprisoned.
Geoffrey R. Stone argues that to understand the Federalist and Republican arguments over the Sedition Act the English law construct of Seditious Libel has to be understood. (more)
