"Van Hollen Asks Federal Court, FEC to Require Donor Disclosure"

"The lawsuit seeks to throw out Federal Election Commission regulations adopted in 2007 that let the groups keep secret the names of donors who pay for pre-election ads. Van Hollen is also the author of proposed legislation to accomplish the same goal. A 2002 campaign finance law named for Senate sponsors John McCain and Russell Feingold required that groups report their ad spending to the commission."

Bloomberg has more.