Lynne, left, Mary, center, and Liz Cheney (Melina Mara/ The Washington Post) Lynne, left, Mary, center, and Liz Cheney (Melina Mara/ The Washington Post)

At the start of the Labor Day holiday weekend — with Congress away, Syria looming large and many Americans consumed by back-to-school chores and last-gasp beach breaks –the politically savvy Cheney sisters publicly clashed over same-sex marriage.

“I am strongly pro-life and I am not pro-gay marriage,” declared Liz Cheney Perry, who at 47 has a husband, five kids and a strong desire to defeat Wyoming’s three-term Sen. Mike Enzi in the Republican primary next August. She has cast her run against Enzi, 69, as generational.

“I believe the issue of marriage must be decided by the states, and by the people in the states, not by judges and not even by legislators, but by the people themselves,” she said in a campaign statement to the Daily Caller Web site. She’s been saying more or less the same thing since 2009, explaining Friday’s anti-gay-marriage campaign statement as a reaction to a push-poll suggesting she was soft on both hot-button issues.

That declaration irked younger sister Mary Cheney, who at 44 has a wife, two children and a strong desire to see same-sex marriage legalized nationwide. “For the record, I love my sister, but she is dead wrong on the issue of marriage,” Mary posted on Facebook. “Freedom means freedom for everyone. That means that all families — regardless of how they look or how they are made — all families are entitled to the same rights, privileges and protections as every other.”

Their father, former Vice President Dick Cheney, supports gay marriage but believes it should be a state matter.

Was the exchange over an issue that is more and more creating fissures within the GOP a spontaneous volley between two high-profile siblings and political progeny? Or was it a calculated set piece aimed at defusing a potential problem for a novice challenger who only moved to Wyoming last year, hoping to beat an entrenched fellow Republican in 2014.

The Cheney campaign accused Enzi forces of dirty tricks for allegedly asking voters in a phone survey if they knew Liz Cheney “supports abortions and aggressively promotes gay marriage?” ABC reported. The Enzi camp denied any involvement, as did the National Republican Senatorial Committee.

Brian Brown, president of the National Organization for Marriage, said the candidate merely paid “lip service” to opposing same-sex marriage.

“Liz Cheney now says she is not ‘pro gay marriage’, but she has long opposed a constitutional amendment to protect marriage as the union of one man and woman. If she truly supported protecting marriage, she would change her position and support both a Wyoming constitutional amendment and federal amendment to protect marriage.”  Enzi, by contrast, “has done more than give lip service to traditional marriage” by co-sponsoring a federal and state constitutional amendment, Brown said in a statement.

In 2009 Liz Cheney told MSNBC that she “certainly would not like to see a constitutional amendment banning” gay marriage.  In that same interview, posted on YouTube by Talking Points Memo, Cheney also said “I applaud, for example, the State Department decision to extend benefits to same-sex partners around the world. It’s wrong to discriminate in those relationships based on somebody’s sexual preference.”

The sisters both were active in the political career of their father, a former Wyoming congressman and vice president under George W. Bush. After growing up in and around Washington — she worked at the State Department, co-founded a national security non-profit and was a Fox News commentator — Liz Cheney moved her family to Wyoming last summeri.

Mary Cheney — who came out in high school to her father and mother, Lynne — has had to tread lightly in a Republican Party reliant on a strongly anti-gay base. She signed a friend of the court brief before this year’s Supreme Court ruling that overturned the section of the Defense of Marriage Act that denied federal protections and benefits to legally married same-sex couples.  Among her jobs in Colorado, where she and partner Heather Poe lived before moving East, was doing outreach to the gay and lesbian community for the Coors Brewing Co.

Cheney and Poe wed last year in Washington, D.C. on the 20th anniversary of their first date, well after the 2009 birth of their second child. They could not marry in Virginia, where they live not far from Dick and Lynne Cheney, because the state outlaws same-sex marriage.

Like many parents of gay offspring, the public positions of the elder Cheneys have evolved over time. During the 2000 presidential campaign, Lynne Cheney blasted journalist Cokie Roberts for raising the question of Mary’s sexual orientation at all. “Mary has never declared such a thing. I would like to say that I’m appalled at the media interest in one of my daughters…And I simply am not going to talk about their personal lives.” Her mother’s rebuke aside, media buzz about Mary’s sexual orientation continued.

But by 2006, a spokeswoman for the then-veep and his wife announced the couple were “looking forward with eager anticipation to the arrival of their sixth grandchild.”

Social conservatives were not nearly as thrilled by the news, including Concerned Women for America.  “It’s very disappointing that a celebrity couple like this would deliberately bring into the world a child that will never have a father,” said CWA’s Janice Crouse. “They are encouraging people who don’t have the advantages they have.”  

The prospective mother called the baby she carried “a blessing from God,” and certainly “not a prop to be used in a debate by people on either side of an issue.” She also assailed her critics, saying “Every piece of remotely responsible research that has been done in the last 20 years has shown there is no difference between children raised by same-sex parents and children raised by opposite-sex parents; what matters is being raised in a stable, loving environment.”

Thomas Mann of the Brookings Institution doesn’t quite know what to make of the siblings’ public spat.

“If this is strategic disagreement between the Cheney sisters designed to boost Liz, it’s as loony as her candidacy,” Mann said. “Maybe they are both being honest: Mary defending herself, Liz showing that her extreme conservative creds are not compromised by personal considerations.”