When Chicago Mayor Rahm Emanuel failed to secure 50 percent-plus-one of the vote in the February municipal elections, leading to an April 7 runoff with Jesus “Chuy” Garcia, progressives and many radicals across the country were elated. Thousands of activists of all stripes have rushed to join his campaign, ecstatic that they might actually be able to defeat an incumbent whose neoliberal policies have proven devastating to all but the ultra-rich.

Recently, however, some on the Left — including Tyler Zimmer in Jacobin — have attacked Garcia, calling him a middle-of-the-road Democrat who, in his unwillingness to endorse concrete progressive policies around policing, economic inequity, and other fundamental issues, offers no meaningful alternative to neoliberalism.

On that last count, Garcia is surely guilty as charged. Progressives would be foolish to whole-heartedly embrace Garcia as some kind of a populist hero. While the Cook County commissioner does have real progressive bona fides and has paid the price throughout his career for running as a reform candidate against the city’s Democratic machine, he has also promised to hire one thousand new police officers — in a city where, according to a new ACLU report, residents are stopped-and-frisked by cops four times as often as in New York City.

Garcia’s much-anticipated plan to right the city’s financial ship offers no concrete, hard-hitting proposals to tax the wealthy or large corporations — in fact, his vow to save money by consolidating the city bureaucracy reads like a thinly disguised assault on the public sector. And though his speeches at rallies are peppered with healthy doses of warm-and-fuzzy populism, he offers few concrete policy proposals that show he intends to take on the rich and go after the banks.

Given the reality that Garcia is not Karen Lewis, the Chicago Teachers Union (CTU) president who was planning to run until she was sidelined by a brain tumor (and recently outlined an unapologetically progressive economic vision Garcia could run on), where are leftists to stand in this election?

Should we reject Garcia’s lukewarm populism, recuse ourselves from the struggle to defeat Emanuel at the polls, and circulate passionate cries for an independent, fighting left alternative that does not yet exist — all while thousands of Chicago union members and neighborhood activists wholeheartedly throw themselves into the fight to elect him?

No, we shouldn’t — we can’t. We have to embed ourselves within the struggle to defeat Emanuel and elect Garcia, push the discourse among that struggle to the left, and fight with every weapon in our arsenal, on every terrain available, to win victories and build power for working people. We can’t build a strong left in Chicago or anywhere else by bowing out of the kinds of fights that are drawing in massive numbers of working-class activists.

And we can’t let our own frustrations at the lack of a strong working-class progressive alternative convince us that displacing a neoliberal Democrat like Emanuel would not build the confidence and sense of power of the city’s grassroots movements — confidence and power that could then be used to achieve much more.

When asked to name the pivotal fighting forces that have paved the way for the movement against neoliberalism and austerity, the CTU quickly comes to mind. Since its radical rank-and-file leadership took over the union in 2010, the CTU has consistently charted an independent path of fierce opposition to Emanuel’s privatization, school closings, corporate subsidies, and attacks on the public sector.

In the years of organizing leading up to this historic election, the CTU, SEIU Healthcare Illinois Indiana, and a number of community groups built strong labor-community alliances, led the fight for a citywide $15-per-hour minimum wage, and injected the issue of racial and economic inequality into the citywide narrative.

This dynamic and expanding coalition has consistently fought for the policies Zimmer calls progressive, such as taxing the rich instead of eviscerating public services and making big banks and wealthy corporations pay for budget deficits. It has identified the banks and large corporations as the real enemies. And in the newspapers, on the picket lines, and within the city council, its successful campaigns to win back corporate subsidies have hit the enemy where it hurts: in the pocketbook .

The coalition has also created independent political organizations (Grassroots Illinois Action and United Working Families) to organize neighborhood-level political power outside of the Democratic machine. Thanks to the efforts of these groups and other activists, independent political organizations now exist in wards across the city.

For example, Tim Meegan, a rank-and-file CTU member who ran an unapologetically radical campaign against an incumbent from a legendary Democratic machine family and missed forcing a runoff by seventeen votes, is now using his members and resources to create a UWF ward-level organization.

This election cycle, these groups helped train and propel community leaders to fight for, and win, seats on the Chicago City Council — expanding the council’s Progressive Caucus, which fought last year to pass a $15 minimum wage, among other things. These organizations are clear and strategic in their plan to build power outside of the Democratic Party, with widespread talk of creating a third party — and yet even they are backing Garcia.

Along with the two strongest progressive unions in the city, thousands of parents, retirees, firefighters, nurses, and community members are hitting the doors and phones every day to elect Garcia. These are the same folks who marched en masse to support the CTU strike in 2012 and to protest the school closings in 2013.

Beyond the machinations of Garcia’s campaign strategists and the pages of his bloodless, spineless financial plan, this is the real Garcia campaign: the movement of thousands of working-class Chicagoans who filled the streets in 2012 and 2013 and are turning out again to fill the halls of campaign offices, independent ward organizations, and union halls to elect Garcia.

Education activists, housing rights activists, mental health activists, beneficiaries of public services, low-wage workers, public workers, and retirees from all across the city are the foot soldiers of the Garcia campaign. How can leftists choose to opt out of such a mass upsurge of working-class Chicagoans?

Zimmer’s piece echoes a number of recent arguments against the county commissioner, including a column last month by Danny Katch criticizing Garcia by comparing him unfavorably to New York City Mayor Bill de Blasio. It ended thusly: “The fight to take back cities like Chicago and New York City from the 1% has to go further than replacing rich jerk mayors with nicer ones. It requires building political alliances and social movements dedicated to much more fundamental and lasting change.”

The irony, of course, is that this is the very reason why many of Chicago’s strongest activists and organizers have embedded themselves so deeply in the Garcia campaign. The movement to elect Garcia builds off the 2012 teachers’ strike and the 2013 school closings fight, and will continue to build long after Tuesday’s runoff.

Our task is to use moments like these to bring broad swaths of the city together in mass mobilizations, and to develop leadership, expand our networks, meet people where they’re at, and work with them to demand more while we’re doing it. In these moments, we feel and test our power, we convince ourselves of our limitless possibilities, we learn the limits of existing institutional structures, and we pour our concerted energies into the achievement of a concrete goal — in this case, defeating Rahm Emanuel, something that seemed like a fantasy mere weeks ago.

If Chuy Garcia defeats Rahm Emanuel on Tuesday, the thousands of Chicagoans who hit the streets in 2012, in 2013, and now in 2015 will, through collective action, experience their sense of powerlessness turned into power. Emanuel, one of the Democratic Party’s mightiest members, will have his aura of invincibility shattered. And the impossible, though still far away, will be a bit more within reach.

After fighting with those Chicagoans now, we will stick by their sides as they keep fighting for $15 an hour during the mass mobilization on April 15; as they keep fighting for strong public sector contracts in the spring 2015 negotiations; and yes, as they keep fighting against the budget cuts Garcia may well attempt to impose in his first city budget this fall.

If we really want to build an independent left alternative, we must implant ourselves in the left organizations that are working every day to build power around the issues that matter to working people. We must push them, extend them, challenge them, and build them. But we can’t simply call out to the masses of Chicagoans and demand they come to us — we must meet the movement where it’s at. And right now, the movement is rallying around Garcia.

As far-right governors and capitalists roll back union power and shred the social safety net throughout the Midwest, the mass movement behind Garcia is one that, at this reactionary moment, we cannot afford to abandon.

There’s a reason that the venture capitalists, speculative traders, and big bankers of Chicago are throwing gobs of cash at Emanuel and not Garcia.

Those movers and shakers of the capitalist class correctly intuit that under Garcia, public sector unions like the CTU will have a stronger hand at the bargaining table; the Progressive Caucus will have a partner with which to craft stronger pro-worker legislation; community organizations will have firmer ground on which to stand against state budget cuts; low-income black and brown neighborhoods will have a better shot at seeing economic development that benefits them; and working-class people, shut out of the Emanuel administration, will have a greater voice in a more transparent and accountable government.

Like any elected official, of course, Garcia cannot just be trusted to represent popular interests. Our task as leftists is to take a sober look at his very real shortcomings; to not kid ourselves into thinking that he is a Karen Lewis or any other kind of strong working-class candidate; to work to educate others of his shortcomings; to push and challenge him from the left; and to continue working to build political alternatives.

But it also should be to fight for his election alongside the thousands of unionists, community members, and working people who are currently rallying around his campaign. Their struggle is one we can’t afford to abandon.