OK, I'm just anticipating the blog headline from the usual blowhards--InstaIgnorance, the Volokh naifs like Zywicki, or William "thank God no one knows what the actual Cornell Law faculty thinks of me" Jacobson--who are beside themselves with paranoid pleasure that the IRS was examining the non-profit bona fides of the various Koch Brothers front organizations posing as "social welfare" organizations. As best I can tell--non-tax lawyer, but literate person that I am--there is a tax exemption for social welfare organizations that aren't primarily poliitcal front groups. But for reasons familiar to anyone awake the last couple of years, the political front groups most likely to be posing as "social welfare" organizations were on the lunatic right associated with the "Tea Party" and like organizations. Their tax-exempt status did indeed demand scrutiny, unless one thought front groups for billionaires (and others) merit special deference when they want to avoid taxes. This is the second decade of the 21st-century, in which, at least in the United States, most "spontaneous grass root" organizations on the right are neither spontaneous nor grass root, and so responsible tax authorities ought to scrutinize them.
Of course, there's a deeper, philosophcal issue here: namely, whether venal groups that shill for the plutocracy can, in any sense, be organizations committed to "social welfare." But the IRS needn't get to the philosophical issue to nonetheless be justified in looking closely.