Tens of millions of dollars have been spent on campaign ads in Iowa leading up to the caucuses. TV commercials blanketed the airwaves, and newspaper ads filled papers from the Des Moines Register to the Sioux City Journal. And for the amount of money that has gone directly into candidates' campaign coffers, it's anyone's guess.
One reason is because of the rise of so-called Super PACS. Following the 2010 Supreme Court ruling in the Citizens United case, groups can raise unlimited funds as long as they don't coordinate with candidates.
Former Minnesota Sen. Norm Coleman is chair of the Congressional Leadership Fund, a Super PAC focused on electing Republican House candidates. He also formed and sits on the board of the American Action Network, a non-profit conservative group based in D.C. He spoke with Cathy Wurzer about campaign finances.