"An action cannot be brought against a manufacturer if, like Mexico's, it is founded on a third-party's criminal use of the company's product," Justice Elena Kagan wrote for the court. Start the day smarter.

The Supreme Court ruled unanimously Thursday in favor of U.S. gun manufacturers and blocked a liability lawsuit brought by the government of Mexico, which sought to hold the companies accountable for the trafficking of their weapons south of the border to fuel violence by the cartels.