ITHACA, NY — Tom Blecher thinks there's only one way Bernie Sanders fails to become the Democratic nominee for president.

"The superdelegates can still take it away from him," says Blecher, 68, a retired electrician and Sanders volunteer. "That's all it comes down to. If the superdelegates are in lockstep with Hillary [Clinton], that might be a problem. Otherwise, Bernie's going to be the nominee."

Nancy Medsker, 60, nods vigorously by his side. "There's going to be a contested convention," she says, clutching a clipboard listing the homes she'll soon be canvassing for Sanders, "and the superdelegates will have to decide: Do they want [Sanders], or do they want to disenfranchise young people and destroy the party?"

I'm at Bernie HQ in Ithaca, a small city in upstate New York that routinely ranks as one of the most liberal in the country. Something of a sister city to Sanders's hometown of Burlington, Vermont, Ithaca may be the next closest epicenter of the "political revolution."

The mood here Sunday morning is upbeat, buoyant. It's a brilliantly clear day, and with two days before the New York primary, new volunteers keep trickling in every few minutes — most of them already decked out in Sanders T-shirts and hats, swapping "Bern" puns, and brimming with confidence that a shocking Sanders upset lies just around the corner.

But underneath the fun, "feeling the Bern" has taken on a double meaning. Sanders's supporters feel burned. They believe their candidate is the rightful heir to the Democratic nomination, despite Hillary Clinton's dominance in votes and in the delegate math. They believe the system is stacked against Sanders, and his expected loss in the New York primary on Tuesday just proves the point.

At a glance, this could be interpreted as a whole town in denial. But there's a real reason for their position: Sanders supporters are drawn to him because he wants to spark a political revolution that blows up the system. The system — from delegate math to voter registration dates — is the reason, they believe, Bernie is behind.

"He's just being massively underestimated," Medsker says. "They treat us like dreamers in the media, but we're not. Bernie's chances in New York are really, really good. I think he's going to win."

To understand why Bernie supporters aren't ready to give up, come to Ithaca.

Inside Bernieland

Susan Sarabasha and a few other volunteers were driving around Ithaca to put down some Sanders yard signs when they saw an unusual sight in the distance.

"We said: 'Oh, my gosh, oh, my gosh, there's a Hillary sign!'" says Sarabasha, 70, during a brief break from hours of phone banking for Sanders.

The news caused something of a stir when they got back to Sanders's headquarters: Is there really someone in town backing Clinton? "I haven't talked to anybody here who is for Hillary," Sarabasha says.

The line on Ithaca has long been that the city is "ten square miles surrounded by reality" — a liberal oasis in a sea of upstate conservatives. Ithacans embrace the caricature, but part of the gag has always been a recognition that its liberalism is in fact out of step with the rest of the state.

This election threatens to change that. As Sanders's campaign gained in both momentum and victories, longtime progressives here say they feel a growing confidence that perhaps Ithaca's far-left tradition isn't outside the mainstream after all.

"It's been fantastic to watch," says Susan Eginton, 57, a Brooklyn native who went to the same high school as Sanders and has lived in Ithaca since 1969. "I've been waiting for a candidate like Bernie all my life, and I'm not surprised at all that there are a huge number of people who also feel like the politicians and mainstream media are ignoring their concerns."

A competing interpretation for the state of the primary

But surely this only goes so far. After all, I point out, Clinton has won several million more votes than Sanders during the Democratic primary.

"That's not actually accurate," responds Gloria Nash, 30. "I think it's a number she's throwing out, but only based on the primaries she won and not the caucuses he won."

The skepticism with official tallies is something I run into a lot at Sanders's headquarters. "It's a bizarre way of counting; it's some weird number she's come up with," says Ithaca attorney Jessica Woodhouse, 47, about Clinton's popular vote lead. "It's apples and oranges, and all of these states are rolled into it that don’t count the same."

Okay, I say. For the sake of argument, let's throw out the idea that Clinton is winning the popular vote by a big margin. She's clearly far ahead of Sanders in the delegate math, and that surely suggests he's likely to lose — right?

"No," Nash says. "Hillary needs 60 percent of the votes left to get the pledged delegates to reach the number that she needs for the nomination."

It is true that to clinch the nomination with pledged delegates alone, Clinton needs 65 percent. But Sanders will need even more — 78 percent — and he's going into very unfriendly territory in the coming primary states, according to most delegate projections, including Vox's.

"The polls published by the mainstream media sources are basically advertising in disguise"

There's been a lot of talk this election season about how virtual communities have reinforced the perspectives of like-minded ideologues, creating powerful new incentives for content that confirms what people want to be true. But in Ithaca, the digital echo chamber is actually compounded by a physical one.

Sanders's name and likeness are all over town — plastered on bumper stickers, storefront windows, barnyards. One restaurant has named a spicy sandwich the "Feel the Bern." Earlier this weekend, Nash and Emma Daley, 27, went to a "Berning Down the House" party in Ithaca held to spread awareness about the primary.

"I just feel like the polls published by the mainstream media sources are basically advertising in disguise," Daley says. "In, like, six of the last seven elections, Sanders has been way behind in the polls and won by these super surprising margins because they weren’t publishing honest polls. It's just so exciting that people aren’t falling for it."

Daley said she's "very willing to believe" election fraud is influencing the results of the primary. She recalled reading an article that claimed Sanders was winning by 17 percent where voters' ballots had been counted by hand, and by only 2 percent everywhere else.

That sounded awfully suspicious. "I'm willing to believe it's possible that more people voted for [Clinton]. But I will not see her nomination as evidence of that," Daley says. "The primaries are run by the parties, and the parties have decided who to elect."

Some Hillary Clinton supporters lay low, if they can

Of course, there are also thousands of Clinton supporters even in the middle of Bernieland.

Perhaps the most prominent is the city's popular mayor, Svante Myrick. Myrick made headlines in the New York Times and ABC News this spring for proposing to legalize heroin injection facilities within city limits.

But that hasn't shielded him from getting routinely criticized by Sanders fans, from the left, as a member of the Democratic establishment.

Within minutes of posting a story to Facebook about Chelsea Clinton coming to campaign in Ithaca, Myrick was inundated with dozens of critical comments. "My simple impression is that you are starstruck and your judgment is impaired," one person said. "Let us know if you can feel your heart when you are in her presence."

The attacks don't go unnoticed. Later on Sunday, I stood in line at Ithaca's organic grocery store — well, one of them, anyway — when I ran into a prominent local official who quietly confided that she can't wait for the primary to be over. She said she spent her Sunday morning reading through the angry comments on the mayor's Facebook feed, and admits the experience made her "incredibly anxious."

"I'm terrified of people here learning I'm voting for Hillary," she said, casting a furtive glance down an aisle of kombucha teas. "Please don't use my name. Seriously."

Is Ithaca in a bubble?

Back in March, I wrote an article arguing that the "Bernie or Bust" movement would "probably go bust" come a contested general election in November.

I think that conclusion still probably holds. But it was becoming awfully difficult to not at least doubt my assumptions when talking to Emily Adams, 51, one of the key organizers of Sanders's headquarters in Ithaca.

Adams talked about extreme poverty in Nairobi when asked to explain the stakes of the Democratic primary, warning, "The whole world could be like that in 10 years if we don’t do something about corruption and the fact that the rich people have everything in this country."

In Ithaca, Sanders is king. But the outcome of the primary will be decided by voters across the state of New York on Tuesday.

"I live in Ithaca, and everyone I know is voting for Bernie," Eginton, who went to the same high school as Sanders, says. "So it may be that I’m in an Ithaca bubble."

Watch: Why voter turnout in New York is so low