Challenges to Tax-Exempt Status

The issue of tax-exempt status of religious organizations is is not one to which I've given a lot of thought, but I note that Catholics for a Free Choice has filed its second complaint asking the IRS to revoke the tax-exempt status of an archdiocese, claiming violation of public charity status based on the archdioceses' efforts to influence voters. This latest was filed against the Archdiocese of St. Louis; the first was filed against the Achdiocese of Denver. Akthough I haven't read the complaint, and as unhappy as I have been at the behavor of some bishops, it is hard for me to see how there is any merit to the claim.
--Susan