IRS nods towards surprising interpretation of civil union/domestic partnership...you may be "married" for tax law purposes

Pat Cain, tax law expert extraordinaire, shared an astonishing piece of news on her blog yesterday.  The IRS Office of Chief Counsel has written a  letter indicating that a different-sex couple in an Illinois civil union is considered married for purposes of filing a tax return at the federal level.  The letter says nothing about same-sex couples, presumably because DOMA blocks treating a