Final answer:
The change to the federal definition of obscenity established the Miller test in 1973, which made it more difficult for the government to censor written material and protected freedom of expression in literature.
Step-by-step explanation:
The change to the federal definition of obscenity was significant in slowing censorship of literature because it established the Miller test in 1973. This test determines whether something is obscene based on three criteria: (a) whether the average person, applying contemporary community standards, would find that the work appeals to the prurient interest, (b) whether the work depicts or describes, in a patently offensive way, sexual conduct specifically defined by the applicable state law, and (c) whether the work lacks serious literary, artistic, political, or scientific value.
Before the establishment of the Miller test, works of literature were frequently banned as being obscene. The Miller test provided a clearer and more objective standard for determining obscenity, which made it more difficult for the government to censor written material. It helped protect freedom of expression and allowed more controversial and explicit literature to be published without fear of censorship.