The US Supreme Court has ruled that Internet file-sharing services will be held responsible if they intend for their customers to use their software primarily to infringe copyright. The Supreme Court remanded the decision to lower courts to review evidence on the services' lawful intent, their marketing, and whether they took easily available steps to reduce infringing uses. Justice Souter, writing for the unanimous Court, ruled that "There is substantial evidence in MGM's favor on all elements of inducement."