Mother Jones obtained a sharply worded email from Armey to FreedomWorks President Matt Kibbe that didn't spell out the reasons for the split, but made a list of demands surrounding his departure.

“Henceforth FreedomWorks shall be prohibited from using my name, image or signature in any way or for any purpose without my written permission or in the event of my death, without my heirs [sic] written permission,” Armey wrote. “Effective immediately, I expect that FreedomWorks shall remove my name, image and signature from all its letters, print media, postings, websites, videos, testimonials, endorsements, fundraising materials and social media, including but not limited to Facebook and Twitter.

“I request that FreedomWorks deliver the copy of my official congressional portrait to my home in Texas,” he added.

In an interview with Mother Jones, Armey said the group was “taking a direction I thought was unproductive.”

FreedomWorks Executive Vice President Adam Brandon confirmed Armey’s resignation to CNN.

"Obviously the elections didn't go the way we wanted," Brandon said. "But we are focused on learning the lessons on what we need to do better heading into 2013."

Conservative groups are grappling with an election that looked promising for Republicans at the beginning of the year, but that resulted in lost House seats and a failure to reclaim the Senate and the White House.

According to The Sunlight Foundation, FreedomWorks spent nearly $20 million on candidates in the 2012 campaign cycle, with only 25 percent of that outlay producing the desired result. Still, that’s better than Karl Rove’s American Crossroads and American Crossroads GPS, which according to Sunlight spent a combined $200 million but didn’t back a single winning candidate.

Freedom Works unsuccessfully targeting a number of Republicans in primaries, including Sen. Orrin HatchOrrin Grant HatchMcConnell names Senate GOP tax conferees Ryan pledges 'entitlement reform' in 2018 Utah governor calls Bannon a 'bigot' after attacks on Romney MORE (Utah), and spending a lot of time and resources on some general-election candidates who lost badly, like Rep. Connie Mack (R-Fla.) in his Senate bid.

— Cameron Joseph contributed

— This post was updated at 9:39 a.m.