Whether he wins the Democratic Party nomination or not—and his chances are increasingly viable—the candidacy of Bernie Sanders has already won, by vastly enlarging America’s political conversation and possibilities.

Like Sanders himself, the significance of his campaign’s remarkable accomplishment should not be underestimated. Against the stultifying tidal wave of the Democratic Party establishment, a dismissive and persistently biased mainstream media, and a nearly 40-year party movement toward the center-right, Sanders has moved political mountains. His achievement reaches beyond his growing arsenal of delegates (amplified by his stunning Michigan upset), beyond his surging prospects as the Democratic nominee, and beyond any “moral victory” of pushing Clinton to the left (which history indicates would be temporary and tenuous at best).

Sanders has reinvigorated the national discourse with an unapologetic, unwavering progressivism—a powerful appeal that’s inspiring a broad swath, from New Deal/New Left Baby Boomers, to working-class and Independent voters, to tradition-skeptical Millennials.

Of course, he has not done it alone. Building on arguments advanced by the Occupy movement and a rising antiestablishment progressivism that has become increasingly forthright about the perils of deregulated capitalism, Sanders has opened up new political space and energy within and outside the Democratic Party. How this energy gets harnessed and directed remains an open question—but it’s more electoral power than progressives have had for decades.

Consider the formidable political walls Sanders has toppled. Dating back to the post-George McGovern drubbing and Jimmy Carter presidency, and gathering pronounced steam under President Bill (Democratic Leadership Council) Clinton, the mainstream Democratic Party has promoted an alienating and inequitable politics of Wall Street centrism. This shift has been marked by deregulatory neoliberal trade policies like the North American Free Trade Agreement, Central American Free Trade Agreement, and Trans Pacific Partnership; a Republican-style “reinventing government” platform (cue Al Gore) that privatizes and diminishes regulatory protections; minimal support for unions; and a tough-on-crime, tough-on-terrorism posture that has helped win elections while losing the war of ideas.

This New Democrat politics (à la Clinton’s and Tony Blair’s Third Way), built over the past 30-odd years, is what Hillary Clinton is endemically a part of; it is in fact the lifeblood of the Clintons’ political careers. But it goes beyond the Clintons. In his presidential rise, Barack Obama spoke in an inspirational, populist voice yet promoted a largely centrist agenda that spoke little of America’s radical inequality and extreme corporate power. Sanders is doing something that no prominent candidate has done with real credibility since Jesse Jackson in 1988—challenging extreme wealth, Wall Street, and inequality while also challenging the Democratic Party itself and the larger direction of politics in America.

Sanders’s accomplishments and credibility now are built on his decades of work fighting for these ideas. When Sanders highlights Hillary Clinton’s support for disastrous 1990s policies such as NAFTA and welfare repeal, he is not simply denouncing her policy stances—he is taking on the Democratic Party’s larger center-right shift. In the Flint, Michigan, debate, Sanders called out the mainstream Democratic Party for aiding deregulatory Clinton initiatives, signaling a larger critique of Democratic centrism. When Sanders criticizes Clinton’s support of the Iraq War and the Patriot Act, he is challenging not only her votes and judgment, but the Democratic Party’s rising militarism and interventionism. (Sanders is not quite the peacenik that, say, Dennis Kucinich was, but he has consistently opposed war and military intervention in favor of coalition building and diplomacy.)

Since their meteoric rise to reinvent the party in the early 1990s, the Clintons and the mainstream Democratic Party (whose establishment leaders have lined up in near-lockstep behind Clinton) have embraced a kinder, gentler form of Reagan-era trickle-down economics—fueling “cooperative” and corporate-friendly regulation, stripped-down enforcement, and a deepening inequality that gave rise to the Occupy movement and its rousing frame of the 99 percent versus the 1 percent. (It’s worth remembering that both Bill Clinton and President Obama presided over “economic progress” marked by historically huge expansions of inequality.)

The message and lingering effects of the Occupy movement, in addition to long-repressed progressive contingents in the Democratic Party, should not be underestimated in considering Sanders’s appeal.

Sanders is tapping into this rich vein of “Enough-is-enough!” outrage and long-simmering alienation in ways that no prominent politician has dared in quite some time. The media emphasis on Sanders’s refreshing authenticity minimizes his deeper importance and resonance: He is not simply speaking with integrity, but speaking truth to power. His phenomenal rise, in the face of staunch (and tone-deaf) opposition from the Democratic Party mainstream, shows that a vast portion of the country is ready for far more significant change than establishment politicians—or most media—dare to admit.

As the nomination battle unfolds, whether Sanders wins or not, the key question becomes: How will progressives, change-minded Independents, and social movements transform this tremendous political energy into a movement that can demand and exact change? Because even in victory, a President Sanders will need a sturdy popular wind blowing his political sails and reform agenda toward success. Given the heavily centrist, pro-corporate core of the Democratic Party, Sanders’s rise should not be mistaken for party overhaul just yet; nor should those supporting Sanders’s agenda put too much stock in the Democratic Party as potential salvation. What’s needed, in one form or another, is an ongoing independent movement that is as truth-talking, principled, and politically brave as Sanders himself.

Sanders has seized and amplified a significant moment in American political history. His remarkable campaign, now seriously contending for the nomination against a political establishment firewall that is rapidly eroding, doesn’t threaten the Democratic Party—it threatens the elite party leadership (the Clintons, the DLC, et al.), which has spent decades distancing itself from (and therefore alienating) working people, the poor, immigrants, and many communities of color. In fact, Sanders’s success actually creates an opportunity for the Democratic Party to be of greater service to its traditional base—working people of all races—by addressing fundamental issues of corporate power and accountability, economic inequality and redistribution, and human priorities over for-profit special interests.

Ultimately, this victory is not about Sanders or even progressives—it’s about creating a shift that could have real consequences for real people. Elections, by definition, are not revolutions. But they create choices and momentum. What Sanders’s achievement signifies goes far beyond mass support for an authentic antiestablishment voice. It means that a huge and growing portion of the country (national polls consistently show Sanders beating all Republicans by significant margins) would like to see at least a goodly measure of economic justice, Wall Street accountability, and truth-to-power political courage. It’s more than the Democratic Party has dared to offer for decades.