FILE - Montana Attorney General Steve Bullock is seen at an event in which he announced the start of his 2012 gubernatorial campaign on in this Sept. 7, 2011 file photo taken in Billings, Mont. Twenty-two states and the District of Columbia are backing Montana in its fight to prevent the U.S. Supreme Court's 2010 Citizens United decision from being used to strike down state laws restricting corporate campaign spending. Bullock argues that political corruption in the Copper King era led to the state ban on corporate campaign spending. A clarification of Citizens United is needed to make clear that states can block certain political spending in the interest of limiting corruption, he said. On Friday, May 18, 2012 Montana's case was given a boost when U.S. Sens. John McCain, R-Ariz., and Sheldon Whitehouse, D-D-R.I., signed on in support. (AP Photo/Matthew Brown, File)