The US Supreme Court has said it will review a copyright law that removes famed foreign works -- everything from Prokofiev's "Peter and the Wolf" to Picasso's "Guernica" -- from the public domain. The government told the court on Wednesday that the 1994 law is necessary to bring the United States in line with global intellectual property conventions, while the plaintiffs say it is an infringement of their right to free speech. Chief plaintiff Lawrence Golan, an orchestra conductor at the University of Denver, said his students cannot play "Peter and the Wolf" without paying royalties. The plaintiffs include musicians, professors and film distributors. "The burden on speech that this statute imposes is remarkable," said Anthony Falzone, a lawyer for the plaintiffs, claiming it extended copyrights to millions of works that had been in the public domain for decades. Their argument has won support from Internet titan Google as well as the American Civil Liberties Union. But Justice Department attorney Donald Verrilli said the law was necessary in order to insure that US property rights are respected in foreign countries. "We are now trying to make a transition into full participation in an international system... which has required an adjustment of our rules," he said. He added that the move to bring the country in line with international rules was "of vital importance to protecting one of our most valuable economic exports, intellectual property." The Supreme Court is expected to rule on the 2001 case before the end of its current session in June 2012.