The role of money in elections was certainly one of the big stories of 2012. But it's been hard to know exactly what the impact of ramped-up spending was. The independent news Web site, Pro Publica, has been investigating the issue. Reporters there have come up with some surprising information. The site's latest story concludes that so-called "dark money" helped Democrats hold a key Senate seat. "With control of the Senate at stake," says Pro Publica, "liberals hit the streets and bought ads for a libertarian candidate who likely siphoned crucial votes away from the Republican challenger."