The left needs its own Tea Party! So goes the axiom as progressives attempt to stand in unified resistance to the agenda of Trump and the GOP Congress.

And so far, the strategy of resistance looks like it may just be working. Millions across the country participated in counter-inaugural protests on January 21, and thousands more crowded into airport terminals this past weekend to protest the President’s Muslim ban.

Just as significantly, committed progressives are reading the Indivisible Guide, a manual for anti-Trump activism written by progressive congressional staffers who observed and absorbed the tactics of the Tea Party. Local Indivisible chapters are forming from Spokane, Washington to Winchester, Virginia, and they’ve already begun ambushing congressional offices and town-hall events. Two weeks ago in Aurora, Colorado, GOP representative Mike Coffman fled his own public event through a side door after discovering that 100 activists had shown up to challenge his position on Obamacare.

The potential emergence of a full-fledged resistance movement is encouraging. If progressives are to defend the rights and achievements of past generations—from Obamacare and Medicare to voting rights and religious freedom—they will need to continue resisting the Republican agenda of 2017 with all of the energy that the Tea Party summoned to resist President Obama’s progressive agenda in 2009.

That said, it is, nonetheless, a mistake to completely recast the progressive movement in the image of the Tea Party. The modern conservative movement has been a resistance movement from the start. Its raison d’être, in the frequently quoted words of William F. Buckley, is to “stand athwart history, yelling Stop.” Tempting as it may be to emulate the conservative movement’s success in unifying the right around a coordinated agenda of resistance, the progressive movement cannot survive on such resistance alone.

Even as progressives work vigilantly to resist the onslaught of regressive federal policies, they should also articulate a long-term vision of a just society and fight locally for a better future. Whether it’s local movements agitating for a livable wage, Black Lives Matter activists working to overhaul local criminal justice systems, or progressive mayors working to address the climate crisis, progressives should continue forward-thinking efforts that look beyond the Trump era. A politics of single-minded resistance would neglect what Walter Lippmann called the problem of “drift.” Many injustices result not from the regressive policies of current decision-makers but instead from this drift of large-scale trends set in motion long before.

Writing in 1914, Lippmann aimed his critique at Woodrow Wilson, who had articulated the “New Freedom” as an agenda of resistance aimed simply at defending the old order of free enterprise and individualism. The problem was that Wilson had highlighted the imminent danger posed by monopolists while ignoring the long-term drift toward industrial capitalism that was generating large-scale dislocation and upheaval. Today, in an era when we are drifting, once again, toward comparable extremes of inequality and plutocratic governance, it won’t be enough to fend off attempts to roll back the achievements and rights gained by past generations. Even if progressives succeed in blocking the main goals of the Trump agenda, the United States will continue to drift toward an oligarchic society, more severe structural racism, and climate catastrophe.

And there is a more important reason why resistance will not be enough to sustain the progressive movement. Progressive politics in the years ahead will be fueled by millennials. Not since the McGovern campaign of 1972 has any young cohort supported a Democrat as overwhelmingly as millennials supported Obama, and the millennial cohort is significantly more progressive than previous generations on a range of issues. These progressive leanings could persist even as millennials age. Notwithstanding the popular idea that we tend to become more conservative as we grow old and jaded, political scientists have known since the seminal 1960 The American Voter survey that partisan loyalty, once established in young adulthood, is not likely to change. Most Americans who came of age in the Depression era, for example, remained lifetime members of the New Deal coalition.

However, this potential could be wasted if the progressive movement becomes so enamored with resistance that it fails to offer, at the same time, a bold, progressive, and alternative vision for the future. The recent election cycle demonstrated clearly that millennials want to be for something rather than just against it. Bernie Sanders’s democratic socialist vision of economic, racial, and environmental justice resonated powerfully with young voters in the primary, while many were clearly unmoved by the anti-Trump message of Hillary Clinton’s general-election campaign. This is a generation that entered adulthood amidst a crisis of capitalism, one that has been saddled with student-loan debt and shrinking career prospects, all in spite of being the best-educated cohort in the history of our country. To fully capture their enthusiasm, progressives will need to imagine, and fight, for a new economic vision.

Notably, many of the most successful justice movements of the past have combined the mantle of resistance with the mantle of progress. The civil rights struggle, which resisted the oppression of an entrenched order, also articulated an inspiring vision of a multiracial democracy. Likewise, South Africa’s anti-apartheid struggle, while fighting for basic survival against a ruthlessly racist regime, simultaneously envisioned a “rainbow nation.” The bold visions of these movements inspired activists to persevere in times of hardship and to sustain their struggles for decades.

These kinds of movements are greatly needed today. We can, and must, obstruct Republican efforts to decimate public services, dismantle the health-care system, and violate minority rights. But at the same time, we should vigorously support the visionary efforts of progressive cities and states, such as California’s aggressive moves to address the climate crisis, New York City’s struggle for a livable wage, and Portland’s effort to reign in executive pay.

At the national level, activists should be using the Indivisible Guide to ensure that all Democratic leaders will fight with every resource available against the Republican onslaught. On the national stage, where creative protest can compete for attention with the President’s bully pulpit, progressive politics should, for the most part, look and feel much like the Tea Party.

But on local and state levels, progressives should follow the precedent already set by progressive cities and states and act constructively to solve problems directly wherever, and whenever, possible. Local initiatives might feel like drops in the bucket amidst the storm of the Trump era, but they are essential for progressive organizing. In these dark times, younger generations will need these beacons of progress if they are to continue believing in a better future despite the calamities of the present.