The feud between Mary and Liz Cheney has ramped up with Mary Cheney taking to Facebook to accuse her sister of regarding Mary and her wife as "second class citizens."

Mary Cheney's wife, Heather Poe, over the weekend suggested that Liz Cheney, who is running for Senate in Wyoming, has taken a position against gay marriage despite embracing their relationship in private. Mary Cheney re-posted Poe's Facebook post, and on Sunday afternoon expanded on Liz Cheney's anti-gay marriage position.

"This isn't like a disagreement over grazing fees or what to do about Iran," Mary Cheney wrote to a commenter on her Facebook page who suggested she should be "lovingly tolerant" of her sister's position. "There isn't a lot of gray here. Either You think all families should be treated equally or you don't. Liz's position is to treat my family as second class citizens. That's not a position I can be 'lovingly tolerant' towards."