Update from a reader:
That group operating out of a Pheonix PO Box – which gave more than $40 million dollars to politically active non-profits in 2010 – is called the Center to Protect Patient Rights. Also, the point that Mayer makes about shared staff and facilities is rapant, and it doesn’t just apply to super PACs. Take FreedomWorks, for example, which has a 501(c)(3), a 501(c)(4), a super PAC, and a regular PAC. They all live at the same address and have the same staff. FreedomWorks’ charitable and “social welfare” arms pick up costs for each other, and FreedomWorks “social welfare” arm is the largest donor to the super PAC. They are by no means the only ones.