Just off the 101 freeway in downtown Los Angeles, a billboard urges teachers to “read this before spending another $1,000 on union dues.” The ad touts teacherfreedom.org, a site sponsored by the Koch-backed California Policy Center that offers instructions on how teachers can leave their union, along with testimonials from people identified as teachers recounting how much freer they felt after leaving their union.

The billboard’s message is that the teachers’ union is a waste of money, an ineffective means to advance their interests. This is not an isolated opinion. Labor’s declining fortunes over the past several decades have given credence to the notion that they are outmoded institutions, and that traditional union tactics like striking no longer work. Recent political defeats like the spread of “right to work” laws and last year’s Supreme Court ruling in Janus v. AFSCME only reinforced that conventional wisdom.

After this week, though, such billboards are less likely to find a receptive audience — and the received wisdom looks increasingly mistaken. That’s because 34,000 teachers learned firsthand that unions really can get them what they want.

They did so by using that traditional union tactic: the strike. Acting together, teachers won what the school board had said was impossible: smaller class sizes, more nurses, counselors and librarians — along with community issues that weren’t even supposed to be on the bargaining table, such as cutting standardized testing, restricting student searches that many considered racial profiling and increasing green space on school campuses.

Despite school board efforts to keep schools open, virtually no teachers crossed the picket lines. Meanwhile, their union, United Teachers Los Angeles (UTLA), organized four rallies of more than 50,000 people in one week, all while running daily pickets at 900 schools. Parents and community members backed the educators in their fight by marching alongside them, even as local businesses brought food to the lines, and local and national political figures spoke up on behalf of the cause. The mobilization caught school board officials flat-footed, while galvanizing teachers and their supporters.

It wasn’t supposed to play out like this. After last summer’s Supreme Court decision in Janus v. AFSCME, many predicted the downfall of public sector unions. That decision allowed public sector workers to opt out of paying for the costs of negotiating and enforcing union contracts from which they benefited. The ruling was supposed to defund unions by allowing workers to withdraw their financial support while maintaining unions’ duty to represent them.

In the wake of the ruling, several anti-union groups organized a concerted nationwide campaign to encourage workers to leave their unions. It includes billboards like the one on the 101 freeway, as well as targeted mail and email messages, and even door-to-door canvassing. “We know there are tens of thousands of educators who chafe under the left-leaning leadership of these unions,” said Jami Lund of the Freedom Foundation. “Making sure they know they now have an option will certainly have its effect.”

So far, it hasn’t. While it is too early to discern long-term effects, initial results suggest that many unions have persuaded more workers to opt in to union membership rather than having more people opt out.

Much of this convincing has been the result of the kind of patient, one-to-one organizing that rarely makes headlines. But victories like the L.A. teachers’ strike are a far better recruitment tool. That’s because they show workers the power they have when they fight together. As Peg Cagle, a math teacher at Reseda High School, told the Nation of the strike, “After decades of feeling invisible, the fact that you really feel like you are being heard, that your voice is rising above the fold, if you will — you have got a possibility that somehow, somebody, might be listening and somebody might actually pay attention.”

Especially in a context where workers’ wages have been slipping for decades, and few feel much control over their lives at work, that kind of show of collective strength transcends the narrow self-interest of the anti-union forces’ “save your money!” message. You can’t put a price on respect.

For unions, the L.A. teachers’ victory offers another important lesson: strikes work. Again, this goes against today’s conventional wisdom, which holds that corporate consolidation, financialization and restructuring have rendered strikes ineffective. In the L.A. teachers’ case, they were not simply up against the school board. They were also taking on wealthy power players like Eli Broad and the Walmart family heirs, who had spent tens of millions of dollars getting their school board candidates elected to create a pro-privatization, pro-charter-school majority on the board.

The Los Angeles strike dealt a setback to that agenda. It did so by shifting the fight over public education from the boardrooms and the ballot box, where the wealthy could effectively buy the results they wanted, out to the schools and streets of Los Angeles, where they were outnumbered. By going directly to the people, the strike positioned UTLA as a voice for the city’s schools and communities, not just a narrow “special interest” looking out for its own members.

This was no accident. It was the result of years of careful planning and deliberate organizing — again, the kind that rarely makes headlines. After taking power in 2014, a reform leadership set about transforming the union and preparing for a strike. They established an organizing department, a political department, a research department and a parent/community division. Working with teachers in every school, they set up Contract Action Teams (CAT) made up of union volunteers and parent representatives. With a 10-to-1 member-to-volunteer ratio, the CATs created a bottom-up infrastructure that could educate and organize the membership, while involving parents and community allies. That’s the kind of organization that was necessary to make last week’s mobilization possible.

The L.A. teachers’ strike shows that with the right planning and organization, strikes can win. Not only that, but they can win things that would otherwise be impossible. Far from an outmoded tactic, they can form the basis for labor’s revitalization.

Following L.A.’s example, teachers in Oakland, Denver and Virginia are also gearing up for strikes. They will be building off last year’s momentum from the “red state” teacher strike wave, as well as recent private-sector strike wins like that at Marriott hotels.

While these mobilizations provide reason for optimism, it remains important to keep them in perspective. Recently released figures from the Bureau of Labor Statistics show that unions continued their decades-long decline in 2018, dropping to 10.5 percent of the nonagricultural workforce. The recent stirrings have yet to shift labor’s fortunes on a broader scale. Additionally, the Janus decision may accelerate membership erosion over time, especially as older union members retire and are replaced by younger workers who have to be convinced to join the union.

But to the extent that a turnaround is possible for labor, the L.A. teachers show the path forward. Methodical workplace organizing, paired with a broad vision and willingness to fight for it, will not win every time. But it’s the only way that labor stands a chance.