William Kristol and his correspondent are deluded. They believe that Hillary Clinton would be a disaster for everything they believe in, but, because they weren't able to pick the person to oppose her, they're supporting her. This is proof, if you ever needed it, that having a doctoral degree from an Ivy League institution is compatible with imbecility.
Addendum: Please don't say that they're not supporting her. They're opposed to the only person who can defeat her. The natural and normal consequence of destroying the only thing that is capable of destroying what you hate is to bring into existence precisely what you hate. If that's not support, then I don't know what support is.