Hope grows at Vermont HQ that the 'Bernie Sanders effect' can go national

It is an unlikely-looking spot from which to plot a revolution. The third-floor suite in Burlington that serves as the national headquarters for Bernie Sanders’ insurgent presidential campaign in fact looks more like a small-town law office: surprisingly busy for a Friday evening, perhaps, but hardly the den of communist sympathisers some Democratic opponents claim it to be.

Related: Dreamers on the campaign trail: 'We cannot vote, but we do have a voice'

In contrast to his frontline base in a faded mall in Iowa , from where Sanders is threatening to upstage Hillary Clinton in next week’s Democratic caucus, the prosperous streets here in Vermont’s biggest city are buzzing with, well, capitalism – a legacy, say locals, of regeneration during the senator’s tenure as mayor in the 1980s.

There are still hints of what Sanders calls his “democratic socialism”. Public transport is unusually well developed for an American city of this size. French-language radio stations remind visitors of its proximity to Canada, whose single-payer healthcare system and family leave policies Sanders wants to emulate in the US.

But the notion that the redistributive tax policies needed to pay for this agenda amount to an assault on American values and a rejection of capitalism is met with wry bemusement by supporters, who dismiss the latest “red scare” mainly as a sign of how rattled their opponents are.

Instead, the mood inside the Sanders headquarters as they prepare for the biggest week of their political careers is a very Vermont mixture of surprise and quiet satisfaction.

“Truth be told, did any of us really, truly in our heart of hearts believe that six months later he was going to be kind of winning?” says environmentalist Bill McKibben as he recalls how far this so-called fringe candidate has come since he launched his campaign from a Burlington park in June.

Perhaps more than any other leading candidate in the 2016 election, the next seven days are make or break for Sanders. If he can beat Clinton in the Iowa caucus, it won’t destroy her or win him the Democratic nomination, but it will raise the possibility that the wave of support could build – first in New Hampshire and then perhaps in Nevada or several super Tuesday states. If the surge dissipates on the prairies of Iowa, even a win in the New Hampshire primary a week later may not be enough to dispel the inevitable feeling that the revolutionary moment has passed.

The last eight polls in a row have put Sanders comfortably ahead in New Hampshire, but only the last two have him ahead in Iowa and most pundits agree the state is effectively a dead heat. Nowhere are people more aware of how precarious the poll lead is than in the bustling advance teams and among the field directors planning his crucial final days before real voting starts.

The momentum has been building and the polls were a reinforcement of that, but we know polls can go up or down

Symone Sanders, national press secretary

“The momentum has definitely been building and the polls were a reinforcement of that, but we know polls can go up or down,” says national press secretary Symone Sanders.

“Literally a poll could come out tomorrow and say the exact opposite, so we try not to get too bogged down in them, but it is exciting. It is extremely exciting. You can feel it. You can feel it here in the office.”

Another set of polls, showing higher success rates against various Republican candidates in a general election than Clinton, have given Sanders more confidence to answer one of the many criticisms he is now facing from his Democratic opponent.

“Within a week of an election, suddenly you start hearing a lot of strange things being said,” he told supporters in New Hampshire on Friday. “And one of the things that my opponent Secretary Clinton is saying is that Bernie Sanders is unelectable; that he cannot defeat a Republican candidate in a general election.

“It gives me some pleasure to present some facts to suggest that that might not be case.”

On one level, the sheer variety of attacks provides some reassurance for the Sanders team. Though some sting more than others, Clinton has yet to settle a single clear message for why President Sanders would be such a disaster.

Though she rightly points out how difficult it would be to implement his bold plans for healthcare, the implied defence of the status quo risks weakening Clinton’s own hard-fought reputation as a reformer.

Others target the senator’s perceived weakness on race and gender, attacking him for not becoming the only candidate to support slave reparations or construing negative comments about Clinton’s endorsement by a women’s health group as a sign of a lack of resolve in defending abortion rights.

Whether these latest attacks add up to much in Iowa, the underlying weaknesses are real. The Sanders camp acknowledges, for example, it was slow to incorporate the specific concerns of Black Lives Matter into its early messaging on inequality, even if it has quickly caught up since them.

When asked by the Guardian if he regretted not making this and criminal justice reform a priority earlier, campaign director Jeff Weaver said much of the strategy was formed on the fly after Sanders decided to run.

“We didn’t spend years planning this,” he said.

The announcement itself came in a shambolic Senate press conference during which Sanders did not even mention he was running. Instead, the first question asked was about his older brother Larry, who was about to stand in the British general election as a candidate for the Green party and is now helping Democrats register for the primary in the UK .

Related: Bernie Sanders puts boots on the ground in Iowa battle with Clinton

The campaign has also been playing catch-up with its own supporters, whose enthusiasm somewhat overwhelmed the small number of paid staff at first. Even now, after a rapid period of hiring, the head office is visibly straining at the seams.

“We are packed in here like sardines, and there are a lot of people who are out on the road,” observes spokeswoman Sanders as she shows the Guardian around.

But it is the grassroots enthusiasm and perceived authenticity that may prove more important.

“Every politician says they are for the little guy; everybody gets that Bernie actually is,” says McKibben, who founded the climate change campaign group 350.org.

“Vermont is a small state. If you were a fake or a phoney you would have been found out long ago. Everybody from Vermont understands, even if they don’t agree with him, that he is the real deal.”

It is certainly a sentiment common among locals not affiliated with the campaign.

“He’s very Vermont: what you see is what you get,” agrees Carol Blattspieler, an orthopaedic nurse, who remembers Sanders’s time as mayor fondly for the restoration of the city’s lakeside waterfront. “Back then, he didn’t comb his hair at all!”

Ask whether someone in Vermont supports Sanders now and you tend to get an indignant “of course”.

The question that will begin to get answered over the next week is whether the rest of the country can become as comfortable with the idea of President Sanders.

guardian.co.uk © Guardian News and Media 2016