Of course, the environment is much better today but US government has a quite rich history of censorship. For example, Memoirs of Hecate County was banned and the Supreme Court upheld the decision in 1948. It was republished after a revision in 1958. Today, it's more about leaks from the government. They're sometimes about
exerting pressure on journalists not to use leaked information or outright trying to prosecute whistle blowers like Snowden. Then you have local and indirect censorship efforts like a pastor having Harry Potter books removed from a school library. Then you have hilarious cases like Texas Education Board banning a book because the author of the book had a similar name to a Marxist author and the board was too stupid to use Google to check it. An interesting case is that of Irwin Schiff, who is banned by a court to sell his book on legal tax evasion.