A full and complete examination of every 501(c)(4) organization for absolute compliance with the intent and law of the IRS regulations would quiet any partisan claims from the process and weed out the groups that are blatantly abusing the tax free status and lack of donor disclosure.
501(c)(4) organizations are generally civic leagues and other corporations operated exclusively for the promotion of "social welfare", such as civics and civics issues, or local associations of employees with membership limited to a designated company or people in a particular municipality or neighborhood, and with net earnings devoted exclusively to charitable, educational, or recreational purposes.