A FTER RATTLING through one of the most radical campaign platforms in American history, inside a craft brewery in snowy New Hampshire last weekend, Bernie Sanders turned to the practicalities. His to-do list, the senator from Vermont acknowledged to his crowd of well-wrapped New Englanders, was ambitious. His promised health-care, education and infrastructure programmes would in fact represent the biggest expansion of government spending in peacetime; by one estimate Mr Sanders would double the federal budget. And he would not be done there. He told the audience of his hope to persuade China, India and Pakistan to redirect their nuclear-arms budgets to fighting climate change. Yet lest anyone considered all this improbable, Mr Sanders offered a reassurance. “Social change happens in radical moments,” he said, citing the struggles of the early labour movement, suffragettes and gay-rights campaigners. “When millions stand up to fight for justice, nothing can stop us!”

To committed Sandernistas, the independent senator is another reason why the political revolution he promises is nigh. A little-known left-winger before his impressive run against Hillary Clinton in 2016, he has since developed a raging personality cult. Attendees at Mr Sanders’s rallies used to wave placards calling for “A future to believe in”. Today their signs often just say “Bernie”. The encomiums his cheerleaders offer him, a veteran professional politician in a baggy suit, are as extreme as his ideas. “It turns out Bernie is a man of the future!” gushed Naomi Klein, his main warm-up act in the brewery, in acknowledgment of the fact that Mr Sanders has been offering much the same critique of the “corporate elite” that he blames for all evils for over three decades. “He was just waiting for the world to catch up!”

In fact there are few indications, in the chilly world outside the brewery, of enthusiasm for the massive changes Mr Sanders promises. His success in 2016 mainly reflected dissatisfaction with Mrs Clinton. And notwithstanding a long-standing and continued leftward drift among Democrats, to which he has contributed, his ideas remain fairly marginal. Mr Sanders’s most popular policy, a universal expansion of Medicare, is backed by 38% of Democrats. That is significant, but hardly augurs the stampede of radical activism he foresees. Despite possessing advantages that most of his Democratic opponents would kill for—including near-total name recognition and an ability to raise millions from his enthusiasts online—Mr Sanders has consistently polled under 20%, less than half the vote-share he won in 2016. He has never looked like challenging Joe Biden as the Democratic front-runner.

Yet two weeks before Iowans get things started, and despite only a modest uptick in his polling, Mr Sanders has started to look more imposing. His fundraising is going gangbusters. He is surging in betting markets. Three months ago they gave him a 6% chance of victory; now he is at 29%. The Democratic establishment is alarmed—led by Mrs Clinton, who this week trailed her assessment of Mr Sanders in a forthcoming documentary: “Nobody likes him, nobody wants to work with him.” What has changed?

As in 2016, Mr Sanders is drawing strength from his opponents’ weaknesses. Mr Biden, a wearier and less articulate septuagenarian, has dominated but failed to unite the centre-left. Sitting atop the Democrats’ biggest faction like a wet sponge, the former vice-president has dampened its ardour, while stifling more inspiring moderates such as Pete Buttigieg. Mr Sanders’s rival on the left, Elizabeth Warren, has meanwhile faltered. By trying to appeal to left-wingers and moderates, she has irritated both. This has made Mr Sanders’s small but committed minority of supporters more significant. If he can unite the left, by convincingly outperforming Ms Warren in the early states, while the centre-left remains divided, he could establish a useful early lead. And Mr Sanders’s especially strong polling in Iowa, New Hampshire and Nevada, where he is currently tied with Mr Biden, suggests this may be on the cards. It was the means by which Donald Trump, another populist with a small but zealous base, won the Republican nomination.

Mr Sanders would still face obstacles Mr Trump did not. In particular, where Republican primaries operate under a winner-takes-all system—which maximised the spoils of Mr Trump’s early lead—Democrats allocate their delegates in proportion to the vote-share each candidate wins. Yet while this would make it harder for Mr Sanders to emerge from the pack, he might still be equipped to do so. His fundraising prowess will ensure he can weather a close contest even as similarly placed candidates drop out. His deep disdain for the hostile Democratic establishment will make him especially determined to do so. Moreover, appearing for the first time as the front-runner, Mr Sanders might be able to expand his appeal across the party more successfully than many imagine.

Authentically crazy

Whatever moderate Democrats may think of his policies, American voters ultimately do not select their leaders on that basis. They mostly choose those they like or feel understood by; and Mr Sanders performs well on such markers. Democrats of all stripes consider his crabbiness authentic and his ideological pigheadedness a mark of integrity. Over 70% say they like him. Those filing out of the brewery in New Hampshire said he was “honest”, “inspirational” and that they “related to him”. Hardly anyone mentioned any detail of a platform that would make the New Deal look austere. And when your columnist raised the fact that Mr Sanders is a socialist, he was gently chided. Most of the rally-goers seemed to consider this a slightly awkward irrelevance.

Given how unfeasible Mr Sanders’s promises are, there is a sort of logic to this. Yet Democrats can be assured it is not an example Mr Trump would follow if he were lucky enough to have an actual socialist as his opponent. If Democrats nominate Mr Sanders, it will be mainly in spite of his radical views. But that would not stop Mr Trump winning re-election because of them.■

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Correction (January 27th): This piece originally said that Bernie Sanders’s campaign slogan was “Bernie” when in fact the official slogan is “Not me. Us.”;“Bernie” is merely an unofficial slogan, albeit extremely prominent at Mr Sanders's campaign events. Sorry.