As much as John McCain deplored Donald Trump, he opened the can of worms that led to his presidency

By picking Sarah Palin for his running mate, he was the unwitting midwife at the birth of proud and impenetrable ignorance as a winning electoral weapon

John McCain’s sense of mischief is mentioned in some of the hagiographies that have greeted his death, but it seemed to desert him at the end.

The senator’s last known wish was that Donald Trump should not attend his funeral. You understand why he wasn’t keen on the tangerine troll, who ridiculed his five-plus years of torture as a prisoner of war in Vietnam, demeaning his internment.

But he blew a chance for payback by not impishly asking the president to give a eulogy. How long Trump could have stayed on message, praising the war hero he hated with the sincerity of the recidivist draft dodger, is anyone’s guess.

Given his habitual struggle with mock solemnity (“Our hearts and prayers are with you!” concluded his consolatory tweet to the family), mine is 75 to 90 seconds. “A wonderful man, such a great maverick. Not such a great navy pilot. I like pilots who don’t crash. I’d have been a tremendous pilot but for the heelbone spurs. The best pilot...”

Then again, perhaps McCain read enough in his final days to regard piling more humiliation on Trump as both inelegant and unnecessary – like the punch Ali never threw as Foreman sank slowly to the canvas in Zaire.

By the skin of his teeth, McCain lived to see the beginning of Trump’s end. Five days before his death came the Cohen-Manafort split-screen courthouse double whammy. In the hours before he slipped away, a triple haymaker combination landed on an already punchy prez’s jaw.

First, it emerged that his closest consigliere and most trusted keeper of dark secrets has done a deal with the Feds. Allen Weisselberg, chief financial officer of the Trump Organisation, has negotiated immunity with prosecutors investigating payments to Stormy Daniels, the porn star and neofeminist icon, and former Playboy model Karen McDougal.

Next, it was revealed that Trump, the John Wayne Bobbitt of the Oval Office, has lost his Pecker. David Pecker, owner of the Trump-beatifying National Enquirer, who apparently bought damaging stories to bury them, also has immunity.

And then, because all good things come in threes, a doorman at a Trump building, one Dino Sajudin, menacingly announced that the Enquirer’s ban on him discussing the love child he claims Trump sired with a housekeeper has been lifted.

If these were the last reports McCain ever read, you hope they ushered him off with a grin about this avalanche of pain snowballing from campaign contribution irregularities. In a more bipartisan Washington era, before “Republican lawmaker” became the accepted shorthand for “filthbag parasitic coward feeding off Trump’s colonic bacteria”, McCain co-sponsored important campaign finance legislation with a Democrat.

He’ll be remembered for more than that, his years in the Hanoi Hilton, never seeing a potential war he didn’t fancy, and the dramatic Senate appearance when already gravely ill to save Obacamare from the Republican wrecking ball.

He will be recalled more generally, and most fondly, as the anti-Trump. His commitment to duty, public service and principle will survive him as a constant rebuke to the man whose grip on the presidency is weakening by the day.

And yet you could argue that, in one of this political age’s more brutal ironies, he was Trump’s chief enabler: that by picking Sarah Palin for his running mate, he was the unwitting midwife at the birth of proud and impenetrable ignorance as a winning electoral weapon.

Palin’s auto-satirical take on the domestic and geopolitical fineries did more than launch Tina Fey into the comedic stratosphere. McCain’s casual embrace of that standard-bearer of the know-nothing, care-less far right, normalised and lionised arrogant imbecility to those who would become the Tea Party, and then the alt-right.

McCain tried to stamp on the zombie retro-racism a black man’s candidacy had released from its flimsy coffin. Memorably, he corrected a woman who interrupted his stump speech to declare that Obama was “an Arab”.

But he had opened a Pandora’s box when he unleashed Palin on America with barely a background check. The next stage in the continuum, Trump’s adoption of the birtherism she proseletysed, powered the candidacy that left little of Obama’s hope in its wake.

Obama will give a eulogy. So will George W Bush, whom with ungodly generosity McCain forgave for smearing him in proto-Trumpian style back in 2000. During the South Carolina primary, Bush’s campaign told voters that McCain was the adulterous father of the black daughter he and his wife Cindy claimed to have adopted. The last bit was true. The McCains adopted Bridget after Cindy brought her home from a Mother Theresa orphanage in Bangladesh.

Whether or not that Muslim-majority nation features as an official “shithole country” on the Trump University atlas, McCain’s love for Bridget qualifies him as a man of unusual humanity by the standards of his party.

Perhaps the latest rumour about a Republican leader fathering a child out of wedlock is equally false. If so, it couldn’t matter less. The end of Trump will have nothing to do with sexual mores his base has always been happy to discount in return for having their racism legitimised.

What cannot be discounted, or contained, is the flow of financial disclosure threatening to become a torrent. If the honour of opening the floodgates falls to the sort of campaign finance law for which he fought so hard, that should posthumously sate the appetite for mischief McCain neglected when he issued his non-Muslim travel ban on Donald Trump attending his funeral.