Do some independent study Bruce. You won't get all the answers from Limbaugh, just the ones you like. The above mentioned groups...Chamber of Commerce and AFSCME, are compelled to report sourcing and contributions as class 527 donors. The recent law change enabled the creation of 501(c) organizations which are not obligated to reveal funds sourcing. They are obligated to reveal spending, but what the hell does that do when an organization named Americans for Reasonable Spending contributes 25 million to a Senate campaign? How do you know the money doesn't come from China? Or from Halliburton? or Ceiba Geigy? You don't.

"The groups are structured as a tax-exempt "social welfare" 501(c)(4) organizations. As part of its tax exempt status, the organizations are allowed to both raise unlimited amounts of money and keep the names and organizations of their contributors secret – an allowance that facilitates groups of this type to raise considerably more money than standard so-called 527 groups which have to report their donors.' ...from the CNN Blog.