Romney was presenting evidence of his viewpoint on Trump, and was expecting voters to trust his viewpoint as it was evidence of what a mainstream prominent Republican thought about Trump. How is that not evidence?
Yes, if you look at it that way it is indeed evidence. In particular it's evidence of Trump's claim to be anti-establishment.
I'm curious about your thoughts on my piece in Salon analyzing Trump's emotional appeal using rationality-informed ideas. My primary aim is using the Trump hook to get readers to consider the broader role of Systems 1 and 2 in politics, the backfire effect, wishful thinking, emotional intelligence, etc.