Liz Cheney on Monday officially abandoned her challenge to unseat Wyoming Senator Mike Enzi in the upcoming Republican primary.

“Serious health issues have recently arisen in our family, and under the circumstances, I have decided to discontinue my campaign,” Cheney, the daughter of former vice president Dick Cheney, said in a statement.

“Though this campaign stops today, my commitment to keep fighting with you and your families for the fundamental values that have made this nation and Wyoming great will never stop,” she added.

Two polls released last year showed Cheney trailing the incumbent Enzi by a wide margin.

Cheney's Senate bid, announced last summer, was marred by her very public dispute on the issue of gay marriage with her openly gay sister, Mary Cheney.

The family feud came to a head in November, when Liz Cheney said during a Fox News Sunday appearance that she loves her sister but doesn't support her marriage.

Mary Cheney's wife Heather Poe responded on Facebook: “I was watching my sister-in-law on Fox News Sunday (yes Liz, in fifteen states and the District of Columbia you are my sister-in-law) and was very disappointed to hear her say 'I do believe in the traditional definition of marriage.' Liz has been a guest in our home, has spent time and shared holidays with our children, and when Mary and I got married in 2012 – she didn't hesitate to tell us how happy she was for us. To have her now say she doesn't support our right to marry is offensive to say the least. I can't help but wonder how Liz would feel if as she moved from state to state, she discovered that her family was protected in one but not the other. I always thought freedom meant freedom for EVERYONE.”

Mary Cheney added: “Couldn't have said it better myself. Liz – this isn't just an issue on which we disagree – you're just wrong – and on the wrong side of history.”

Speaking to a group in Indianapolis working to derail a proposed marriage ban in Indiana, Mary Cheney argued that marriage equality is a conservative value.