Carney: Cheney infighting shows gay marriage a 'tough issue' for families

White House press secretary Jay Carney said Monday that public infighting between members of the Cheney family over gay marriage was evidence that the subject remained a difficult one for many Americans.

"With regards to interfamily dynamics, obviously, this is a tough issue and can be a tough issue for a lot of families," Carney said. "But it is a very American value to pursue equality for everyone."

The White House spokesman said he hadn't discussed the controversy with President Obama, but credited former Vice President Cheney for his public support of gay marriage.

"I would simply say that, like so many Americans, former Vice President Cheney has come to view equality as something that, well, we need to make fact and not just an aspiration. And that is certainly where the president is," Carney said.

Liz Cheney, who is running for the U.S. Senate in Wyoming, said she opposed same-sex marriage in a television interview with Fox News. She faces a tough primary with incumbent Sen. Mike Enzi (R-Wyo.) in the deep red state.

That led to a strong rebuke on Facebook from her sister Mary Cheney, who is a lesbian, and her wife, Heather Poe.

"Liz - this isn't just an issue on which we disagree - you're just wrong - and on the wrong side of history," Mary Cheney wrote.

Poe, in a separate post, called her sister-in-law's response "offensive."

"When Mary and I got married in 2012 - she didn't hesitate to tell us how happy she was for us," Poe said. "To have her now say she doesn't support our right to marry is offensive to say the least."

In a statement earlier Monday, the former vice president and his wife, Lynne, said they were "pained" by the public argument between their daughters.

"This is an issue we have dealt with privately for many years, and we are pained to see it become public,” the couple said. “Since it has, one thing should be clear. Liz has always believed in the traditional definition of marriage. She has also always treated her sister and her sister's family with love and respect, exactly as she should have done."