Lawrence O’Donnell has been making a cogent argument why the IRS scandal is rooted in an error made in interpreting the tax code that dates to 1959. Apparently the actual law and original interpretation was that 501(c) orgs consist of “Civic leagues or organizations not organized for profit but operated exclusively for the promotion of social welfare.”

However in 1959 the IRS ruled, without any change to the law, that “[A]n organization is operated exclusively for the promotion of social welfare if it is primarily engaged in promoting in some way the common good and general welfare of the community.”

In other words they defined down the term exclusively so that it meant “not exclusively.” This opened the door to all kinds of political advocacy.