501(c)(3) — Religious, Educational, Charitable, Scientific, Literary, Testing for Public Safety, to Foster National or International Amateur Sports Competition, or Prevention of Cruelty to Children or Animals Organizations
501(c)(4) — Civic Leagues, Social Welfare Organizations, and Local Associations of Employees
Contributions to 501(c)(3)s are deductible to the donor; contributions to 501(c)(4)s are not. Acorn was a 501(c)(4). Contributions to that organization were NOT deductible. Many 501(c)(4) organizations, including Acorn, had affiliated 501(c)(3) charities that operated as non-political units. Voter registration is an acceptable charitable activity.
501(c)4 vs 501(c)3 vs 527
Acorn may be one of the most misunderstood groups of all-time. It was unduly vilified shortly after the last election. Perhaps you are one of those people that does not really understand what ACORN was about and would like to be better informed on the topic to sharpen future posts:
Association of Community Organizations for Reform Now - Wikipedia, the free encyclopedia
Its not as if the inter-city poor have much of a lobbying effort; Acorn pretty much was it. One of the reasons they were big into voter registration was to try to encourage their constituency to effect change through the power of the vote (as opposed the the correct answer in America, is that you effect change through the power of the checkbook) I don't think the world is a better place without them.
BTW... the voter fraud in ACORN was actually a fraud against ACORN. They hired poor workers and college students and paid them based on the number of voter registrations they turned in. Given the thousands of people that did this job and the fact that pay was piecemeal, it was not unexpected that the workers would turn in bogus entries.... of course, RW radio turned it into something that it was not....