“By supporting, I mean not working, not contributing, and not voting for (I’m registered in Virginia not Wyoming)," Mary Cheney wrote in an email.
She added that she isn't necessarily rooting for incumbent Sen. Mike Enzi (R-WY) to defeat her sister.
“I am not saying I hope she loses to Enzi," Mary Cheney said.
A family feud bubbled to the surface this week after Mary Cheney and her wife, Heather Poe, criticized Liz Cheney over her opposition to gay nuptials.
Mary Cheney said she hasn't spoken to her sister since the summer and the two will not be seeing each other on Christmas.
The public quarrel prompted their father, former Vice President Dick Cheney, to release a statement in which he defended Liz Cheney's position on same-sex marriage.