By Andrew Chung

The U.S. Supreme Court on Monday declined to hear North Carolina's defense of a state law aimed at preventing hidden-camera investigations from damaging farms and other businesses in a challenge brought by People for the Ethical Treatment of Animals (PETA) and other animal rights groups.

The justices turned away appeals by North Carolina's Democratic Attorney General Josh Stein and a trade association representing North Carolina farmers of a lower court's ruling that the 2015 law violates the U.S. Constitution's First Amendment right to free speech when enforced against "newsgathering activities."

PETA has said it conducts undercover investigations to expose the abuse of animals in laboratories, farms and slaughterhouses, the pet trade, clothing industry and other areas. The organization has said it had wanted to conduct an undercover investigation of animal testing labs at the University of North Carolina but feared the state law's threat of monetary damages.

PETA, the Animal League Defense Fund and five other organizations sued in 2016 in federal court to block the law's enforcement, saying it punishes the free speech of whistleblowers.

The law allows a business or property owner to sue "double-agent" workers who make secret recordings or remove documents from non-public areas and use the information to "breach the person's duty of loyalty to the employer," to recover monetary damages for the violations.

Plaintiffs and critics have called the measure one of several "ag-gag" laws around the country aimed at restraining the undercover actions of animal rights activists. The state, represented by Stein, said the law would protect all employers against a wide range of harms, such as unauthorized use by employees of trade secrets, campaign strategies or patient information.

The Richmond, Virginia-based 4th U.S. Circuit Court of Appeals ruled in February that the law violates the First Amendment when enforced against "newsgathering activities," such as those pursued by PETA and the other plaintiffs. Stein told the justices that "newsgatherers have no First Amendment right to break generally applicable laws," such as against trespassing.

Various activist organizations on the left and right carry out undercover investigations intended to expose wrongdoing, sometimes being accused of selectively editing video to make their subjects took bad.

(Reporting by Andrew Chung in New York; Editing by Will Dunham)