The treatment of Sarah Palin during the campaign was the work of Steve Schmidt, who recommended her. He recommended Sarah and then sabotaged her. Now he is a vocal anti-Trumper SOB who left the GOP over President Trump’s immigration policy.
The epic failure of the McCain campaign and Schmidt's inglorious role in it put an end to his career as a GOP consultant. A friend of mine who was hired for McCain's general election campaign described its epic disorganization and the astonishing scene every Sunday as a couple of dozen of McCain's campaign paladins and senior NRC strategists gathered at his palatial ranch in northern Arizona, with McCain at the head of the table.
The strategy meeting was usually held at the outdoor barbecue pavilion, with a meal and drinks beforehand catered by McCain family servants. The campaign staff and attendees might begin the meeting in a structured manner, but they were soon diverted by McCain asking for more detail, posing questions, and launching into jokes and stories of war and politics.
Every weekend, the result was a constant backlog of campaign management issues unaddressed and decisions unmade, which McCain might (or might not) take up chaotically during the ensuing week. One does not need a graduate degree in psychology to recognize that was how McCain wanted things, vainly and foolishly maximizing his role in the management of his campaign.
Due to character flaws, McCain sabotaged his campaign, but he contrived to have the glory of making some of the best GOP talent available sitting at his feet, awaiting his favor. As for Palin, I think that, initially, McCain liked her maverick ways. Soon though, he soured on Palin due to the enthusiastic GOP grassroots approval of her as injecting new life into a flagging campaign effort. And so, from McCain to Schmidt to Wallace, the order went out to serve Palin up to the news media.