This IRS restraint was doubtless reinforced by the fact that virtually all politically active (c)(4)s, mostly labor and environmental groups, were ideologically liberal and their activities were not attacked in the mainstream media or by the political establishment.

WSJ: David Rivkin and Lee Casey: The IRS and the Drive to Stop Free Speech

But he said Congress was partly at fault for not giving clear instructions about when politically active 501(c)(4) organizations cross the line.

WSJ: Treasury Officials Knew of IRS Targeting Last June

Following the ruling, the number of politically oriented groups seeking tax exempt status as social welfare organizations under section 501 (c) (4) of the federal tax code increased greatly at a time when the federal government, including the IRS, was dealing with austerity measures that reduced or stagnated personnel and resources.

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