Michael Warren at The Weekly Standard:

The National Organization for Marriage (NOM), a pro-traditional marriage organization, alleges that confidential tax forms were either leaked or stolen from the IRS and illegally distributed by its opponents to the media.

...A spokesman for the IRS told the Daily Caller that it takes confidentiality “very seriously” and will be conducting an investigation into the possible leak.

Eastman and Brown have also sent letters to HRC president Joe Solmonese and Huffington Posteditor in chief Arianna Huffington. NOM argues that by publishing the form, both organizations are in violation of federal law regarding tax return disclosure. The code NOM cites reads as follows: "It shall be unlawful for any person to whom any return or return information...is disclosed in a manner unauthorized by this title thereafter willfully to print or publish in any manner not provided by law any such return or return information." The letters also claim that both HRC and the Huffington Post are liable for civil damages as a result of the publication of these forms.

Each letter contains attached screenshots of HRC’s website showing the confidential forms as they were originally posted there. Those forms have since been removed, although they remain accessible through the Huffington Post.

“I do believe they are wholeheartedly serious,” Brown says of the IRS and its investigation. Brown adds that NOM’s lawyers say that such a leak of an individual non-profit group’s tax forms is “not normal” and that he suspects the HRC was engaging in foul play.