Actually the Sedition Act was used all the way through the
Vietnam war. The basic purpose behind the act was so that the
government would have a way to quiet individuals that were behaving in an "
unpatriotic" manner. During World War I it was used to give lengthy prison terms to people who war protesters, and others. An ironic example is that the maker of the film
Spirit of '76, an early film showing the fight against the
British during the revolution. He was given a 7 year prison term because the film "Tended to characterize our good allies, Great Britain, in an unfavorable light."
This is an amazing piece of legislation in that it almost entirely voids the
first amendment.