There was no evidence. There was only speculation. It was after the election and McCain's people were blaming Palin for the defeat - pretty much the same McCain people who are on MSNBC now every week bashing Trump.
One political consultant who worked for McCain in the South Carolina primary wrote up something about Romney people in the McCain campaign bashing Palin to smash a possible 2012 campaign by her. How did he know? He didn't cite any names. He didn't produce any evidence.
Did he have any first-hand knowledge? Did he hear rumors? From whom? And what was that, second-hand? Third-hand? Or even more remote rumors? Did he find clues and put them together? Was he just deducing that this was something that Romney would do? Or did he just deliberately make the story up to make Romney look bad or McCain's team look good?
We don't know. Of course it caused a lot of discussion, but you can get a mountain of discussion out of a grain of speculation. Your version, that Romneyites in the campaign were bashing or bad-mouthing Palin all along, wasn't supported by anything at the time. It was something people concluded or assumed later on the basis of the other rumors.
You seem to be extremely suspicious, yet also naïve. Politicians and campaign operatives run the opposition down (preferably with words, not with cars, though that may have happened sometimes). That's what they do. That's what you're doing here. It's something I've done.
People speak their minds. Nobody is above criticism. But the idea that there was some massive Romney-originated subversion of Palin before the election is not proven. I suppose anything is possible, but this is something people invented based on what they think of Romney.
I don't like Romney much myself. He's a rich guy who thinks his good fortune makes him virtuous (or his virtuousness makes him wealthy). But I spent much time back then researching this rumor to find anything behind it and came up with nothing but speculation.
But it's the nature of myths and legends that one can't convince true believer that they may not be true. I'll leave it at that.
I was here then, every day. It happened. This guy amassed a record of sabotaging GOP opponents that got in his way. He sabotaged a Republican in MA, Jim Rappaport, that wanted to run WITH him for Lt Governor. He obliterated Rappaport in order to put a useless cypher on the ticket who couldn’t win an election of her own accord. Rather than depart with a strong candidate to succeed him, he left the hack Healey, who was promptly run over by Deval Patrick.
Palin was hugely in his way, and she had to be taken care of. I say again, I never absolved the McQueeg people also being in on the sabotage, albeit for different reasons, but that doesn’t mean Willard wasn’t guilty as well. Backstabbing while maintaining a phony pious façade of morality and character is his premier hallmark.
An established pattern of misconduct and sabotage is more than enough evidence for any rational person. If you require more, that’s on you. Until then, when I see a homeowner who just took out a huge insurance policy on their house standing a few feet away from some gasoline and a match, I’m gonna figure they’re not there to roast marshmallows. Guess that makes me suspicious and naïve.