I generally wait until the funeral to say something unfavorable about the recently deceased, but I feel like this doesn't count because my take on John McCain is merely mostly negative: the self-created myth of "John McCain, Man of Honor" rested on one shallow foundation block. John McCain was a man who did a some really awful things in his life, but every time those things blew up on him and made him look awful, he went way above and beyond to redeem whatever honor he could.
So the thing he's most famous for is using his father's pull to get himself assigned to Navy fighter pilot school because he thought that was his best way to get hot babes, because hot babes love fighter pilots. He was shot down over Hanoi in the act of bombing civilian targets. The Communists tortured him into confessing to bombing civilian targets, which John McCain resisted heroically because he was genuinely dumb enough to believe the shallow excuse that we weren't bombing Hanoi, we were bombing military targets in and around Hanoi -- despite the fact that the President of the US was on TV night after night bragging about bombing Hanoi, while Secretary of State Kissinger talked openly to any reporter who would listen about how we were bombing North Vietnam's capital city in an attempt to wrest further concessions out of them.
But once thrown into the Hanoi Hilton as a war criminal caught in the act, McCain went to genuinely heroic lengths to protect and uplift the men now under his command; he may have been one of America's greatest ever Senior POW Officers. A dozen or more men say that the only way they lived through their time in the Hanoi Hilton and stayed sane was because of the lengths their Senior POW Officer went to on their behalf. So you have to give him that.
He then parlayed that fame into a successful Senate run where he rapidly acquired a reputation as a really stupid person who thought he was really smart. That made him easy prey for Charles Keating, a horrifying scammer who kept McCain in a steady stream of easy cash, free resort vacations, and the endless company of pretty young "lobbyists" hired to tell McCain how smart and handsome he was. In exchange, John McCain tried to tell banking regulators that they had to be wrong when they said that Charles Keating was a crook. Charles Keating was obviously a very wise and honest person, because he was one of the only people in America wise enough and honest enough to see and say just how smart and how important John McCain was.
People, Charles Keating was convicted of paying John McCain a bribe that John McCain was acquitted of accepting, because people sincerely believed that John McCain was so vain and so dumb that he could have honestly not realized he was being bribed.
And that is why John McCain went on to become America's loudest, staunchest champion of getting corrupt money out of politics, the cause that got him labeled a centrist Republican and made him a Democratic darling -- it was the only way that John McCain could convince himself, and the public, that he wasn't a corrupt guy who tried to protect a professional crook in exchange for a six-figure bribe. But because he was trying just as hard to sell "John McCain, Man of Honor" to his own stupid self, he didn't just make a few gestures and fall back on that -- he really plugged away at that cause for the rest of his life.
John McCain served as a vivid reminder that you don't have to be smart or even terribly moral in your daily life to be a hero; being a hero just requires stepping up and taking the risks and doing the right thing once you DO realize that you have to. Even if you are doing it out of vanity and stubbornness, it's still heroism. So there's that in his favor, too.