The California Supreme Court has ruled that a court may issue an order prohibiting a defendant in a defamation case from repeating statements about the plaintiff that were deemed defamatory at trial.
The concern about such a ruling is that an injunction is a "prior restraint" and would be a violation of the right of free speech. But the California Court thought to the contrary, and said that "preventing a person from speaking or publishing something that, allegedly, would constitute a libel if spoken or published is far different from issuing a posttrial injunction after a statement that already has been uttered has been found to constitute defamation. Prohibiting a person from making a statement or publishing a writing before that statement is spoken or the writing is published is far different from prohibiting a defendant from repeating a statement or republishing a writing that has been determined at trial to be defamatory and, thus, unlawful."
The opinion has a nice collection of law around the country that reaches a similar result. The dissent does a fine job collecting opinions to the contrary.