Bernie Sanders might resemble Larry David – but none of his competitors are laughing now

Underestimating Sanders has proved a mug’s game. With a couple of arterial stents for running mates, he is halfway to doing a Lazarus

Even by the cosmically bizarre current standards of Anglo-American politics, the latest twist in the meandering race to take on Trump is a doozy.

In late September, Bernie Sanders was a widely discounted long shot. The self-described socialist senator from Vermont came unexpectedly close to beating Hillary Clinton to the Democratic nomination four years ago – but by this point, pushing 80 and a distant fifth in the polls, he looked done.

Conventionally, the presidential contender’s comeback trail starts with a high-profile endorsement, a sparkling debate or some other sign there’s life in the old dog yet.

But this old dog has never been conventional, and the catalyst for Sanders’ recovery was a flirtation with death.

In early October, Sanders had a heart attack everyone assumed would end his campaign. Three months later, he is living proof of the saying about what doesn’t kill you. He is joint favourite, with Joe Biden, for the Democratic nomination.

Sanders may resemble a geezer who bemusedly wandered into presidential politics off the set of Old Jews Telling Jokes. Yet while he may be a ringer for his cousin Larry David, none of the other candidates are laughing at him now.

Those candidates constitute an engagingly diverse crew so far as age, background, sexual orientation and political outlook are concerned (though less racially diverse after the withdrawals of Kamala Harris and Corey Booker).

Biden is also nearing 80, while 70-year-old Elizabeth Warren is almost twice as old as Pete Buttigieg, the ex-soldier and small-town mayor who is married to a man. A couple of apparent no-hopers will join them tonight in Iowa for the last televised debate before nomination season officially kicks off there next month.

Michael Bloomberg, who intends to buy the nomination by spending a billion or two of loose change on advertising blitzkriegs, won’t be among them.

But Bernie will be, alongside Biden in one of the frontrunners’ spots at centre stage, in Des Moines, the state capital whose name, according to humorist Dave Barry, translates as “some of those Moines over there”.

By the time you read this, the debate might have clarified what, at the time of writing, remains the least predictable election in memory.

The polls differ as to who has the edge in the Iowa caucuses. Any of the above-mentioned quartet could win. Yet whichever of them emerges triumphant will take the momentum to New Hampshire and beyond; whoever underperforms may cease to look electable. Iowa won’t decide what promises to be a drainingly attritional marathon, possibly all the way to a brokered convention – but it will shape it.

Writing before this crucial debate, I find myself wildly conflicted about Bernie. Like progressives the world over, I love the Old Testament prophet-style righteous anger about the iniquities of the untempered free market. He rages at its cruelties with eloquent passion – and offers less fanciful solutions than Warren, his rival on the Democratic left, with her multitrillion-dollar spending fantasies.

The paramount question for Democrats – if not the only one – is who has the best shot at slaying the tangerine kraken.

The internal struggle between head and heart – eternally the dilemma for progressives – has seldom felt starker.

The heart screams for Bernie. The head whispers Biden, riotously disappointing though he is.

Neither may end up taking the nomination, of course. Warren might revive, with or without the aid of a cardiac event, though probably not thanks to allegedly telling Warren a woman couldn’t win the White House. With the bedazzling Alexandria Ocasio-Cortez as chief cheerleader, Sanders is well protected against a he-said-she-said charge of sexism.

A win in Iowa and a strong showing a few days later in New Hampshire could allow Buttigieg to steal the pragmatic centre ground from Biden. And who knows: Bloomberg’s limitless arsenal of cash bombs could blow the bleeding lot of them out of the water.

At this moment, however, this has the makings of a two-way title eliminator for a crack at the gravest threat to planetary security since the Cold War.

Underestimating Sanders has until now proved a mug’s game. With a couple of arterial stents for running mates, he is halfway to doing a Lazarus. Whether completing the renaissance would come to be seen as a tragically Pyrrhic victory, with Trump ridiculing the oath to protect the constitution a second time, is the painful judgement Democratic voters need to make.

The outcome of the general election will probably turn on six or seven states, several of them in the rust belt, where Biden’s blue-collar, Amtrak-riding relatability seems a far snugger fit than Sanders’ romantic radicalism.

The drawback to romance is its pesky knack of ending with a broken heart. It befits the topsy-turviness of our age that the Democrats’ renewed love affair with Sanders started with one. Whether the Democrats have the strength to curb their enthusiasm in the cause of removing Trump, however, is yet to be seen.