"A defining aspect of the American tradition is that groups of citizens band together for a wide variety of civic purposes. They recruit volunteers, raise funds and spend those funds to promote whatever project or cause brings them together.
"For more than a century, our tax laws have recognized that such voluntary associations -- non-profits, we call them today -- should not be taxed, because their proceeds are devoted entirely to improve our communities through education, advocacy, and civic action. Section 501 of the Internal Revenue code recognizes them today, and civic groups like Move-on-dot-org, the League of Conservation Voters, the ACLU, the National Rifle Association and various taxpayer groups have always been included in this definition."
Excerpt from House floor remarks by Congressman Tom McClintock, April 17, 2012. Text link: http://mcclintock.house.gov/2012/04/irs-harassment-of-tea-party-groups.shtml