Attorneys general from nearly half of U.S. states have come out in support of a Montana law limiting corporate spending on elections. The century-old state law was struck down following the Supreme Court’s decision in Citizens United, which opened the floodgates for more corporate money for political campaigns. But the Montana Supreme Court later upheld the law. If the U.S. Supreme Court considers the case, it could change the way states are allowed to regulate corporate money in elections.