Mary Cheney, the lesbian daughter of former U.S. Vice President Dick Cheney, posted on Facebook on Friday night that her sister, who is running for the Senate in Wyoming, is "dead wrong" to oppose same-sex marriage.

Liz Cheney, who is opposing Republican Sen. Mike Enzi in a primary next year, released a statement earlier in the week saying: "I am strongly pro-life and I am not pro-gay marriage. I believe the issue of marriage must be decided by the states, and by the people in the states." Cheney issued the statement after a poll conducted with voters raised the question of where she stands on same-sex marriage.

Mary Cheney married her longtime partner, Heather Poe, last year in Washington. Their father announced in June 2009 that he backed same-sex marriage, though he thought it was a decision best left to the states.

"For the record, I love my sister, but she is dead wrong on the issue of marriage," Mary Cheney wrote on Facebook. "Freedom means freedom for everyone," she added. "That means that all families are entitled to the same rights, privileges and protections as every other."