Last month, thousands of people marched for science in more than 600 cities and towns globally. It was an amazing public display, but for the march to turn into a successful movement, it has to keep building political power — not just for science and scientific institutions, but for the communities that science serves.

That’s what I took away from the words of Dr. Mona Hanna-Attisha, the Flint, Michigan-based pediatrician who exposed widespread lead poisoning in her community, who spoke to marchers in Washington, DC. She used her power as a scientist to fight the corrupt state agencies that oversaw the city’s water delivery and sanitation systems.

“Flint is what happens when we dismiss experts. Flint is what happens when we dismiss people,” she told the March for Science crowds. “It is time for all of us to step out of our clinics, our classrooms and labs,” she declared. “We need to make ourselves known in the halls of government. We need to hear all of your voices.”

She then introduced Mari Copeny, also known as Little Miss Flint. Copeny told the crowd that Flint’s children knew their water was tainted, that they were lied to by the state, and that they relied on people like Dr. Hanna-Attisha to expose what was happening. “Flint kids are smart,” she said, “and we’re brave, and, most of all, we’re strong.”

And the people of Flint are stronger today because scientists like Dr. Hanna-Attisha are on their side.

Stories like hers should ground our discussions about science and politics. Too often, researchers of all stripes get hung up on philosophical debates over how or whether they should publicly engage with politics. But such debates don’t cure diseases, put food on anyone’s table, or protect children from lead poisoning. What does help to accomplish those things is serving our communities and becoming strong advocates for science that advances the public interest. That’s also what builds political power for science: making sure it really helps make people’s lives better, and demonstrating by example that we all benefit from supporting research and evidence-based policy.

Indeed, scientists who are worried about problems like budget cuts, censorship, and a growing lack of regard for authoritative sources of information should know that solving those problems will involve more than standing up for science for its own sake. It will involve standing shoulder to shoulder with the people who should benefit directly from the work that scientists do.

Many researchers and their supporters marched in Washington to protest shrinking budgets for several science-based agencies, pausing to take pictures outside the headquarters of the embattled Environmental Protection Agency, which could face steep cuts under the next round of budget negotiations. In Brazil, marchers organized a “scissor orchestra” to protest the cuts that have already hit science agencies there.

But fighting those cuts isn’t just about protecting scientists or labs or data sets. It’s about standing up for and protecting our communities from dirty air and water and preventable diseases. For basic research funding, it’s also about standing up for the role science can play in pushing new technology from the lab to the marketplace, where it can create new jobs, especially in places that are hurting economically.

Other marchers protested scientific censorship. In the United States, the March for Science itself began to take shape after the National Park Service was prompted, under the new Trump administration, to freeze its Twitter accounts, and as scientists and technologists scrambled to back up federal data repositories that were vulnerable to deletion. In other parts of the world, the stakes are even higher for some scientists and academics, who can face jail time for speaking out. But fighting censorship isn’t just about the intrinsic value of free speech in science, vital as that is. It’s about fighting for the public’s ability to have access to, and benefit from, research that they paid for with their tax dollars.

Many people marched to emphasize that “facts” and “evidence” don’t change in response to our political leanings. In Jackson Hole, Wyoming, the march ended with the song “Science is Real,” by the band They Might Be Giants, and thousands of homemade signs, in protests spanning the globe, carried variations on the assertion that “Facts > Opinion.” But that epistemological point often distracts us from a much more fundamental and practical one: The greatest danger of misinformation is that it can become the basis for harmful public policy, from legislators voting to ignore sea-level rise, to school districts allowing parents to opt-out of life-saving vaccines for their children.

Addressing these problems requires people, power, laws, and lobbying — all of it the stuff of politics. It is my hope that the march has helped scientists and people who lead scientific institutions see that politics doesn’t have to be about partisanship, nor does it have to involve compromising one’s integrity. On the contrary, politics is — or ought to be — about making our communities stronger, safer, and healthier. So, too, with science.

The good news is that scientists still have significant power and influence in policy circles. But at a time when all our institutions are under threat, retaining and growing that power means sharing it with our communities. That means a grassroots movement for science will surely involve things scientists are used to: giving more talks, hosting more public events at scientific venues, and meeting with legislators.

But it should also involve deeper civic engagement that builds power not just for the scientific community, but for the communities that scientists serve. That means participating in town hall meetings, volunteering with local advocacy groups, and fighting discrimination that prevents people from accessing science and scientific careers. It means registering and mobilizing voters who care about science. For some scientists, it will also mean taking the ultimate step in public service and running for local, state, or national office.

A grassroots movement for science can succeed, but only if it holds the people that science is supposed to serve — laborers, homemakers, educators, farmers, students, families — in the same high regard as scientists themselves.

Aaron Huertas is a Washington, D.C.-based science communications consultant whose clients include a variety of grassroots science, environment, and climate advocacy organizations. He runs ScienceCommunicationMedia.com, and volunteered on a national organizing committee for the March for Science.