Citizens United decision meant that corporations could pay for political ads, using social welfare
nonprofits as a shield of secrecy...
In January 2010, the Supreme Court ruled that corporations and unions could spend money directly on election ads. A later court decision made possible super PACs, the political committees that can raise and spend unlimited amounts of money from donors, as long as they don't coordinate with candidates and as long as they report their donors and spending.
"Initially, campaign finance watchdogs believed corporations would give directly to super PACs. And in some cases, that happened. But not as much as anyone thought, and maybe for a reason: Disclosure isn't necessarily good for business. Target famously faced a consumer and shareholder backlash after it gave money in 2010 to a group backing a Minnesota candidate who opposed gay rights.
Many watchdogs now believe that large public corporations are giving money to support candidates through social welfare nonprofits and trade associations, partly to avoid disclosure. Although the tax-exempt groups were allowed to spend money on election ads before Citizens United, their spending skyrocketed in 2010 and again in 2012.
A New York Times article based on rare cases in which donors have been disclosed, sometimes accidentally, explored the issue of corporations giving to these groups last year. Insurance giant Aetna, for example, accidentally revealed it gave $3 million in 2011 to the American Action Network, a social welfare group founded by former Sen. Norm Coleman, a Republican, that runs election ads."
http://www.commondreams.org/headline/2013/05/23-1