Catholic voting guide indicates that it is a sin to vote for President Obama

[skepticscott]

5. They are not prohibited per se

if they only serve to delineate the policy positions of the various candidates, for the purposes of voter education, but they can be violative of tax exempt status if they are so blatantly biased as to constitute a de facto endorsement, or a clear message NOT to vote for one candidate over another, as appears to be the case here. The other issue is whether the organization distributing them IS a tax-exempt organization, or gets money from one.