A wide grin spread across Bernie Sanders's face as he looked out at a massive crowd of more than 20,000 supporters in Oakland, California, in May.

"When we began this campaign a little over a year ago, the pundits had determined in their never-ending, never-failing wisdom that this was going to be a 'fringe' campaign," Sanders said, his tone dripping with irony. "A year has come and gone, and up until now we have won the primaries and caucuses in 23 states. We have won over 9 million votes ... and we're going to win in California."

Sanders finally admitted defeat in the Democratic nomination in Tuesday, congratulating and endorsing Clinton. But on the narrower question of whether the pundits understood the potential of his campaign, Sanders is clearly right: He's proven anything but a "fringe" candidate in the Democratic primary.

The vote totals don't tell the story alone. Sometime over the course of a 14-month campaign, nine Democratic debates, and what seemed like a never-ending number of town hall forums, Sanders somehow crossed the barrier from obscure Vermont senator to genuine cultural sensation.

Nearly every announcement he makes now prompts dozens of stories. His face has been all over late-night television. He’s become an international celebrity, inspired a clothing line and a dating app, and gotten an audience with the pope.

Most importantly, Sanders's big ideas — the "political revolution," "democratic socialism," the cry to take on the "millionaire and billionaire class" — have been injected into the American political vocabulary as those of few other candidates ever have.

Nobody knows exactly what kind of lasting impact Sanders's candidacy will have on the Democratic Party. But for this campaign cycle at least, he's fundamentally reinvented what almost everyone assumed what was possible.

Here's a look back at five ways Bernie Sanders changed the story of 2016.

1) Clinton's nomination was inevitable. Until it wasn't.

"Hillary Clinton has nothing to worry about as she prepares for the Iowa caucuses." — Bloomberg News, May 2015

"Hillary Rodham Clinton is poised to win the Democratic nomination without a serious contest." — Nate Cohn in the New York Times, April 2015

"Kim Kardashian Has a Better Chance of Being President Than Bernie Sanders." — Charles Krauthammer, of the Washington Post, June 2015

Before the 2016 presidential primary began, nearly all the bigwigs in the Democratic primary lined up behind the scenes to back Clinton's candidacy.

Beyond former Maryland Gov. Martin O'Malley, all that appeared to stand in her way was a motley crew of little-known outsiders and political has-beens — Lincoln Chafee, who was enmeshed in a frog scandal as governor of Rhode Island; Jim Webb, who bizarrely boasted about killing someone at the first debate; and Sanders. Critics talked of Clinton's "coronation."

They were proven wrong. Sanders began with surprisingly strong fundraising numbers, and young people started showing up for his rallies. He rose steadily in the polls, gaining serious ground on Clinton as early as July 2015. The press talked of "the summer of Bernie."

After a surprisingly close finish in Iowa, Sanders smashed Clinton in New Hampshire by a massive 22-point margin. He then got trounced in several Southern states on March 1, giving Clinton the big delegate advantage from which Sanders never recovered.

But Sanders put wins on the board, and in places few expected — not only in largely progressive states like Minnesota and Colorado but also in swing states like Michigan and Wisconsin, and in conservative states like West Virginia and Oklahoma that few expected would ever back anyone near a democratic socialist label.

At one point, Sanders pulled even with her among Democratic primary voters in national polling. Then came the New York primary, which Clinton won in a landslide, followed by big wins in states like Pennsylvania and Connecticut.

Sanders could never quite break through with enough minority voters to win the primary. But there's no doubt he demolished the idea that Clinton's nomination would prove a cakewalk.

2) A radically new way to pay for a presidential campaign

That Sanders gave Clinton such a scare may be the most impressive aspect of his candidacy. But his lasting legacy may be pioneering an essentially unprecedented funding model that let him stay in the race.

Most experts had assumed all successful presidential campaigns would have to be either independently financed or rely on wealthy backers. Even Barack Obama, who generated a large network of small donations, tapped Wall Street and "campaign bundlers" for donations.

But Sanders rejected all forms of big campaign contributions as inherently corrupting, instead relying almost exclusively on a small-donor army that nobody thought could foot the enormous multimillion-dollar cost of a modern presidential campaign, according to Bob Biersack, a senior fellow at the Center for Responsive Politics.

It worked. Sanders raised so much money from small donors that he even outspent Clinton by more than 50 percent throughout on advertising, according to NPR.

As I reported in March after Sanders raised more than $77 million from those giving under $200 each:

Sanders's model represents a break from what political consultants consider the traditional way of fundraising: Compile a Rolodex of wealthy donors, then tap them and their friends for the maximum $2,700 contribution. "That's the way national campaigns usually go," Biersack said. Sanders has at least proven that there are the dollars and the contributors to power a national presidential campaign essentially through small donors alone. "There is really another way," Biersack said.

3) A clarion call on the danger posed by widening financial inequality

Sanders's small-donor revolution fits with another way he changed the story of the 2016 primary: by making the growing gap between America's wealthiest and poorest into the defining issue of his campaign.

"At a time when millions of American workers have seen declines in their incomes and are working longer hours for lower wages, the wealth of the billionaire class is soaring in a way that few can imagine. If you can believe it, between 2013 and 2015 the 14 wealthiest individuals in the country saw their net worth increase by over $157 billion," Sanders said in June 2015. "We live in the one of the wealthiest countries on earth, yet children go hungry, veterans sleep out on the streets, and senior citizens cannot afford their prescription drugs. This is what a rigged economic system looks like."

The point is not so much that Sanders discovered income inequality or was the first person to make it into a campaign issue, but that he did so with more consistency and urgency than anyone else. Until Sanders, few candidates had so aggressively thrust inequality to the top of their agenda — or framed it as an existential crisis that threatened the essential stability of the country.

Indeed, Clinton began talking about wealth inequality at her campaign launch. But she clearly ratcheted up her passion and rhetoric over it when faced with the Sanders insurgency, according to Dave Hopkins, a political scientist at Boston College.

"[Clinton] obviously cared about it, but I’m not sure it would have been as much a part of her basic message as it is because of Bernie’s challenge," former Pennsylvania Gov. Ed Rendell told Politico.

Beyond the Democratic nominee, Sanders also appears to have convinced millions of his young supporters to adopt his views on the dangers of "casino capitalism," according to a study by the Harvard Institute of Politics.

"He's not moving a party to the left. He's moving a generation to the left," the institute's polling director told the Washington Post in April. "Whether [...] he's winning or losing, it's really that he's impacting the way in which a generation — the largest generation in the history of America — thinks about politics."

4) Forcing a $15 minimum wage into the Democratic mainstream

At the outset of the campaign, it was unclear whether the Democratic Party would throw its weight behind the "Fight for $15" movement calling for a $15-an-hour minimum wage across the country. Clinton sent mixed signals, praising the campaign in the abstract without endorsing its specific goals, and center-left wonks were (and remain) ambivalent.

But Sanders was unrelenting on the question, demanding from the start of his campaign that anything short of the $15 minimum wage was unacceptable.

"It is not a radical idea to say that if somebody works 40 hours a week, that person should not be living in poverty," Sanders said in defense of the idea.

By April, Clinton clearly felt the heat, and in a Democratic debate against Sanders she announced that she would sign a bill mandating a $15-an-hour minimum wage as president.

"Despite Clinton's past insistence that she only supported a $12-an-hour minimum wage, [Sanders] helped push her to switch positions and back a $15-an-hour minimum," wrote Vox's Dylan Matthews after the debate.

There's good reason to believe the victory was far more than symbolic. Research has found that presidents' campaign promises affect how they govern, suggesting Clinton's rhetorical concession to Sanders could really translate into a real-world change.

5) A Clinton reversal on a major free trade deal

Hillary Clinton spoke out 45 times in favor of the controversial Trans-Pacific Partnership trade deal from 2009 to 2013.

Then in October 2015, she suddenly reversed course: She announced she would instead oppose the trade deal she once claimed represented the "gold standard" for trade deals.

"Her explanation for why she's coming out against the deal now — after years of supporting it — makes no sense," Vox's Timothy Lee wrote. "She cited two specific objections: It doesn't have language dealing with currency manipulation, and it has provisions that favor big drug companies over patients. These are totally plausible arguments for opposing the TPP. But they make no sense as reasons for Clinton to change her mind about the treaty."

Of course, we know the real reason Clinton dramatically reversed course on the trade deal, the big variable that changed between 2013 and her decision: Bernie Sanders.

"The Trans-Pacific Partnership is a disastrous trade agreement designed to protect the interests of the largest multi-national corporations at the expense of workers, consumers, the environment and the foundations of American democracy," Sanders said in one press release. "The TPP is a treaty that has been written behind closed doors by the corporate world."

It's unclear how much Sanders's supporters actually care about his message on trade and how much they're merely parroting what they've heard from him to exit pollsters. As I reported in March after the Michigan primary, many reporters have overstated the link between Sanders's criticism of NAFTA and his success on the campaign trail — especially since young people tend to support free trade deals.

But there's no doubt that Sanders himself cares deeply about the dangers posed by free trade deals. And there's little doubt that he alone probably changed where the presumptive Democratic nominee stands on it too.