A judge in Utah has ruled that the 'ag-gag' law - which makes filming and photography to document abuse in animal agriculture illegal - is unconstitutional.
The law was passed by the Utah State Legislature in 2012, targeting animal welfare groups who filmed abuses to back up their allegations.
But at the end of last week, US District Court Judge Robert Shelby claimed the law violates the First Amendment right to free speech.
He wrote in his ruling: "Utah undoubtedly has an interest in addressing perceived threats to the state agricultural industry, and as history shows, it has a variety of constitutionally permissible tools at its disposal to do so.
"Suppressing broad swaths of protected speech without justification, however, is not one of them.
"In sum, it appears the consensus among courts is that the act of recording is protectable First Amendment speech."
Judge Shelby became involved in the case after the arrest of activist Amy Meyer, who filmed a cow outside a slaughterhouse.
Following the judge's ruling she said: "Four years ago, I stood outside a slaughterhouse in Draper and filmed a sick cow as she was being pushed with a front-end loader, as though she were nothing but a piece of garbage.
"I was shocked when I was the one charged with a crime instead of that animal’s abusers. It should never be a crime to tell the story of an animal who is being abused and killed, even if it’s for food. Today’s court ruling is a vindication for anyone who stands up for what’s right and tells the truth."