Terry Gross interviewed Liz Cheney on Fresh Air on Dec 5. To expand and clarify, using Cheney’s own words from the transcript (available at the link):
GROSS: Did you vote for him twice?
CHENEY: I did.
GROSS: So I’m curious. Like, what did you see in him in the sense that - you know, certainly even before the first election, he was so litigious as a businessman. There were so many lawsuits against him and so many lawsuits that he filed. He made claims about his finances that weren’t true. He bragged about being able to grab women by their genitals because he was a celebrity… [snip…Terry enumerates trump’s crimes and faults] So why did you want to vote for him for a second term?
CHENEY: Well, I certainly wish I hadn’t.
…
CHENEY: I think that, you know, certainly I was representing Wyoming and the policies that the Trump administration - not necessarily him, but the policies the Trump administration put in place in areas like energy policy, land use management policy, some of the things that really mattered for my constituents in Wyoming, some of the issues that mattered with respect to national security, in terms of defense spending. There were issues that I’d been working on that I thought were very important for Wyoming, I still think are important for Wyoming and for the country. And I think what people need to know now going into this next election is that just can’t be an option. And as Republicans and as Americans, we have to be able to find a way where we can advocate for those kinds of policies where we aren’t having to choose someone who’s shown that he has a complete lack of respect for and willingness to abide by his oath to the Constitution.
…
CHENEY: … Now, the issue, though, is that right now we’re faced with a choice between - you know, if you have to say, look, the country can sustain several years of bad policies.* We cannot sustain somebody willing to torch the Constitution. And no matter where you are in terms of saying, I made the decision at this moment or this moment, once you get through January 6, once you get through him trying to seize power and overturn an election, you know, there’s no - that’s a line that can never be crossed. And there’s no defense for that.
The upshot is that Liz is still committed to Republican policies (no surprise there) but that Jan 6 was a bridge too far for her and trump cannot be voted in as president again.
* I took “bad policies” to mean Democratic policies. That is we can live with whatever the Democrats come up with because however bad we Republicans think their policies are, they aren’t trying to destroy the government.