The scale of the challenge Bernie Sanders faces is well-established. In Hillary Clinton, he will square off against the most overwhelming non-incumbent front-runner either party has seen since the dawn of the modern nominating process. And while the odds that he’ll actually defeat her are vanishingly slim, he may nonetheless be better-positioned than any other Clinton challenger to at least make her break a sweat.

The 73-year-old Sanders will be back in his hometown of Burlington, Vermont, Tuesday evening for what will technically be his second declaration of candidacy. Meeting a self-imposed deadline, he made a brief statement announcing his intention to run in Washington at the end of April. Consider Tuesday the ceremonial kick-off, a more traditional rally with a more comprehensive statement of purpose by the candidate. Those close to Sanders say he was genuinely torn over whether to run right up until his statement last month, but now he’s fully committed to the race – and acutely aware of what he’s up against.

Related: Bernie Sanders makes the pitch for free college tuition

It’s easy to dismiss Sanders as nothing more than a niche candidate, an avowed “democratic socialist” with a diehard following on the far-left. Raising money will be a challenge and Sanders will rely heavily on modest contributions from grassroots donors. His outsider posture and distance from the Democratic establishment also means he won’t be reeling in many high-profile endorsements. (Just last week, Vermont’s Democratic governor, Peter Shumlin, snubbed Sanders and threw his support to Clinton.) Nor does Sanders have much of a campaign infrastructure in place right now.

But write him off completely at your own peril, because Sanders actually has a few things working in his favor. There’s his message, for one thing, a frontal assault on the political system and a pledge to directly combat the “billionaire class.” This is hardly new talk from Sanders, who has been on Capitol Hill for 24 years now, but the climate has shifted since the 2008 economic meltdown and income inequality, wealth concentration and corporate power are unusually prominent in the national debate. And with economic anxiety still high and rampant frustration with Washington’s paralysis, there’s a potentially wide opening for a damn-the-system crusade like Sanders is leading.

It’s more than that, though. There’s also his personality and his image – grumpy demeanor, disheveled appearance, disinterest in discussing anything not related to policy, contempt for personal questions. He is the antithesis of a packaged political candidate and his authenticity is a powerful tool. Look at it this way: Former Maryland Gov. Martin O’Malley, who is poised to join Sanders in the Democratic race later this week, is planning to stress many of the same economic themes as Sanders. But which one of them sounds like he means it more? Sanders’ team can’t afford polling yet, but they are quick to point to his strong favorable/unfavorable scores in public surveys as proof of his potential appeal.

Close video Time to make room for more presidential candidates Sen. Bernie Sanders will officially launch his 2016 campaign in Burlington, Vermont. The senator, who is technically an independent, is the first Democratic challenger to Hillary Clinton. Msnbc’s Alex Seitz-Wald joins with more from the granite state. Sen. Bernie Sanders will officially launch his 2016 campaign in Burlington, Vermont. The senator, who is technically an independent, is the first Democratic challenger to Hillary Clinton. Msnbc’s Alex Seitz-Wald joins with more from the granite state. share tweet email Embed

His appeal is broader – or potentially broader – than most assume. In Vermont, Sanders has built a formidable coalition not only of Democrats and liberals but also of economically downscale conservative white voters. Here it’s worth noting that Sanders routinely votes against gun control measures and ventures into culture war politics rarely and grudgingly.

The good news for Sanders is that he’s gained more early polling traction than any of the other Clinton challengers –O’Malley, former Virginia Senator James Webb, and former Rhode Island Governor Lincoln Chafee. He’s also shown himself to be a star on social media, where his policy ruminations regularly go viral, and his team bragged of bringing in $1.5 million in the 24 hours after his announcement of candidacy last month. His team hopes to raise $50 million this year – not nearly enough to rival Clinton, of course, but plenty to build out full-fledged operations in all of the early primary and caucus states.

At a minimum, the Sanders team believes he’ll be able to emerge as the de facto non-Clinton candidate. Already, there are encouraging signs for them on this front. A recent Iowa poll put Sanders at 14%, more than O’Malley, Webb and Chafee combined; and a New Hampshire poll gave him 18%, more than doubling up the other three. (That said, he still trails Clinton by around 50 points.)

Related: How Bernie Sanders won the talk radio primary

The venues for the lead-off contests are favorable for Sanders: Iowa and New Hampshire, two states with small, rural populations that aren’t too different from Vermont, where Sanders has now won ten statewide elections. The leftward, activist-oriented bent of Iowa’s Democratic caucus electorate is well established; it’s the state where Clinton finished in third place in 2008 the beginning of the end of her first presidential campaign. And right on Iowa’s heels will come New Hampshire, where Democrats already know Sanders as their next-door neighbor.

Realistically, Sanders could fare surprisingly well in these two states, knock the other non-Hillary candidates out of the race, then gobble up 20-to-30% in primaries and caucuses throughout the spring and arrive at the convention with hundreds of delegates – enough to command attention and shape the platform.

Of course, you don’t subject yourself to the exhausting and occasionally humiliating rigors of a national campaign without believing on some level that maybe, somehow, you might actually strike gold. So here it is – the scenario that exists somewhere in the minds of everyone in Sanders World: He scores a breakthrough performance or two in televised debates with Clinton (there are six scheduled right now); then he finishes a surprisingly close second in Iowa, resulting in a wave of press coverage about Clinton’s sudden vulnerability, and follows it up with the unthinkable: an outright victory in New Hampshire; with that stunning, Sanders then reaps a Hart ‘84/McCain ’00-like windfall of media coverage and campaign donations while party leaders begin revisiting their assumptions about the vitality of Clinton’s candidacy. And once that happens …

You can decide where in that scenario the thinking shifts from hopeful to delusional, but the one-in-a-gazillion shot where it all works out is the fuel that keeps every longshot campaign chugging along. And while it’s true that we’ve never seen a frontrunner like Hillary Clinton before, we haven’t quite seen an underdog like Bernie Sanders either.

Take the Bernie Sanders quiz