Sen. Bernie Sanders (I-Vt.) in Emeryville, Calif., on Monday. (Elijah Nouvelage/Reuters)

Eight years ago today, Hillary Clinton ended her presidential campaign after a long and bitter Democratic primary fight. Tonight, by the time the votes are counted in California, Clinton is expected to secure enough delegates (including pledged delegates and endorsing superdelegates) to make her the party’s presumptive nominee, even as Sen. Bernie Sanders (I-Vt.) plans to press onward until the Democratic convention next month.

For those of us who supported Sanders, the inevitable disappointment at falling short will be joined with deep pride and excitement about a campaign that electrified so many progressive voters nationwide. If past is prologue, we can expect the political and media establishment to eagerly cast aside Sanders and his talk of a revolution. But while the primaries may be coming to an end, the political revolution that Sanders has been leading for the last year may be just beginning — if Sanders and especially his supporters remain steadfast in pursuit of the larger goals that have fueled his campaign.

Indeed, when the Nation’s editors endorsed Sanders in January, we praised his “clarion call for fundamental reform,” but we also argued that his campaign was about the future of progressivism as much as winning the White House in 2016. “His run has already created the space for a more powerful progressive movement and demonstrated that a different kind of politics is possible,” we wrote. “This is a revolution that should live on, no matter who wins the nomination.”

Clinton may take the nomination, but Sanders surely has won the political debate. He started at single digits in the polls and was widely dismissed as a “fringe” candidate. He has astounded even his supporters, winning more than 20 contests, 10 million votes and 1,500 pledged delegates, the most of any true insurgent in modern history. He has captured the support of young voters by record margins. And he did so less with personal charisma than with the power of his ideas and the force of the integrity demonstrated by spurning traditional deep-pocketed donors in favor of grass-roots fundraising. Harvard researchers found that Americans between the ages of 18 and 29 have actually become more progressive over the course of the campaign. Sanders hasn’t merely won a seat at the table, he’s started a sea change in Democratic politics that the party will have to adjust to.

Even as Clinton turns her focus to Donald Trump, Sanders will play a major role over the next five months. At the convention, we will witness a powerful demonstration of the passion that Sanders represents. His allies will seek to ensure that the Democratic Party platform incorporates the fundamental reforms that he has championed — from the $15 minimum wage and Medicare-for-all, to tuition-free college and breaking up the banks, to rebuilding our infrastructure and getting serious about climate change. He will use his prime-time address to lay out the next stage in the political revolution, while showing that stopping Trump is vital to its progress.

And with his massive army of passionate supporters, Sanders can continue to fundraise and campaign for progressive candidates in congressional races across the country, helping to grow the ranks of leaders who share his vision in Washington. He’s already endorsed strong insurgents such as Zephyr Teachout, Pramila Jayapal and Lucy Flores.

Looking ahead to 2017, if Democrats take back the Senate, Sanders is in line to become chairman of the powerful Senate Budget Committee. As a leading member of the Democratic caucus, he can wield the influence he’s earned during his campaign to keep pushing his colleagues — and, hopefully, a Democratic president — to embrace more progressive positions on key issues. Meanwhile, having awakened a new generation of progressive voters to politics, he can help make sure that young people don’t sleep through another midterm election cycle in 2018, reversing a damaging trend that has helped the Republican Party seize and maintain control of Congress.

While Sanders has already indicated he will endorse Clinton if she captures the nomination, neither he nor any leader can deliver the votes of his supporters. That challenge is Clinton’s. Sanders has already nudged Clinton to the left on key issues during the campaign, including trade policy and the minimum wage. The Democratic National Committee made one important concession last month by allowing Sanders to name five strong progressive allies to the platform committee (though the DNC also vetoed one Sanders pick, National Nurses United executive director RoseAnn DeMoro, on the strange grounds that it did not want labor leaders on the candidate’s lists).

Clinton’s challenge now is not only to gain Sanders’s support, but also to earn the enthusiasm of his voters. Sanders won young voters and Democratic-leaning independents by staggering margins. Clinton should not assume that the threat posed by Trump will suffice to get them to turn out for her in large numbers. She has to move from being the candidate of “No We Can’t” to one who offers real change to those in desperate need of it.

Most important for the future of our politics and country will be the trajectory of the political energy that the Sanders campaign has helped to galvanize. As my Nation colleague D.D. Guttenplan reports, some movement activists are already starting to pour their energy into initiatives, such as the People’s Summit and Brand New Congress, to sustain the momentum from the Sanders campaign. “What Sanders himself decides to do with the power he has acquired is enormously important. Ultimately, though, what his people — Bernie’s Army — do with their power is even more important,” he writes.

The Democratic establishment wants Sanders and his supporters to report for duty and line up behind Clinton — to put aside their dreams, forget the bitterness of the primaries, and enlist. This is, for many, an unrealistic expectation. Sanders and his supporters are building a political movement both inside and outside the Democratic Party. They have their own agenda. They will support their own candidates and drive their own issues. They are proud — and should be proud — of what has already been built.

But what they should see clearly is that while the political revolution this country needs is far more profound than anything Clinton has ever championed, the defeat of Trump is essential to its progress. If Clinton becomes president, the movement can continue to build its momentum. If Trump wins, its activists will be forced to refight battles of the past — on race, on top-end tax cuts, on nativism, on choice — rather than push a new agenda for the future.

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