McCain’s populist formulation struck a chord with the party base, which had little innate interest in reducing the tax burden on the rich. But the Republican elite viewed McCain with perfect horror. His attempt to reimagine the party in populist terms, rather than as a vehicle for the upward redistribution of wealth, posed an existential threat. The fight they waged in South Carolina reflected their understanding of the danger of his apostasy.
McCain was a lot of things. But there is a white-washing by his media friends of some of the serious foul shit in his past to paint him as a not-Trump.
Two words: Sarah fucking Palin.
He stood by as George W Bush and Karl Rove slandered an American war Hero, John Kerry (who should have lost to Howard Dean) with the Swift Boats Vets for Truth bullshit.
After Karl Rove and Bush slandered the hell out of McCain in 2000 he rolled over for them when it came time to stand on principle for the Iraq votes in 2003.
The savings and Loan Scandals. Google that rabbit hole if you dare.
And that is just the top of the pile.
His legacy, once all his friends are dead, will be complex. I think that there may have been a man in there, somewhere, that really wanted to make the country better. I may disagree with most of the ways he wanted to achieve his goals, but I'll work with someone who wants my country to succeed, not just strip mine it and ship its wealth off to Wall Street and elsewhere. But at the end of the day he was just too in the middle to be effective on the big important issues.