Earlier this year scientists announced that on April 22—Earth Day—they intended to, in their own words, “walk out of the lab and into the streets.” Organizers of this March for Science were dismayed by a new administration and a Congress pushing policies likely to increase pollution, harm health, reduce our ability to forecast natural hazards such as hurricanes—and toss accepted science out the window. The protests, planned for Washington, D.C., and other cities around the U.S. and the globe, quickly gathered support from major scientific societies, tens of thousands of volunteers, hordes of Twitter supporters and 800,000 members in a Facebook group.

It's a start—but not enough to make a lasting impression on the president, Congress or state legislators.

“Don't tweet at them. Don't sign goofy-ass useless internet petitions. Call,” tweeted David Shiffman, a marine biologist at the University of Miami. He is right. People need to reach out individually to members of the government and make it clear that they will back their opinions with votes.

Protest marches can be effective. The civil-rights demonstrations in the 1950s and 1960s showed politicians that a huge number of people opposed prejudice and segregation and were willing to take action. The March for Science could do the same thing. Rush Holt, chief executive officer of the American Association for the Advancement of Science—and a former U.S. representative for New Jersey as well as a physicist—said that his organization supported the march because President Donald Trump's election has triggered many attacks on evidence and rational thought as guides to national policy. He was also alarmed by politically based attacks on the integrity of the scientific enterprise. There are concerns that Trump supporters and conservative politicians will dismiss the march as nothing more than the whining of elites. As a result, some scientists were reluctant to get involved—but many others were all in.

There are ways, however, to make sure the marchers' message will linger in politicians' minds after the crowds disperse. Scientists can run for office themselves, and a new group called 314 Action, named for the first three digits of pi, is recruiting. Funded by some 80,000 donors (as of March), 314 Action, co-founded by Shaughnessy Naughton, a chemist, will give both money and political training to scientist-politicians. Naughton has enlisted the help of political campaign strategist Joe Trippi, who has guided several Democratic candidates into congressional seats.

Running for office is, in many ways, an unscientific endeavor. Campaigns are not controlled experiments, and rough-and-tumble real-world politics can be an uncomfortable new experience. But Kate Knuth, an environmental scientist who served several terms in the Minnesota House of Representatives, told the Atlantic that she learned invaluable lessons knocking on strangers' doors and asking for their votes. “I never felt like I knew more about how people were thinking about the problems in their community, what they wanted from government, and their hopes and dreams for the future,” Knuth said.

Those who do not run can vote and let politicians know that votes, like science, will follow the evidence. People can call state or federal representatives and say that if they do not act to support—to pick one example—the National Oceanic and Atmospheric Administration's offices that predict storm severity or coastal erosion, representatives will lose at the ballot box. Scientists and ordinary citizens can also donate money and time to groups that advocate for government policies that are backed by scientific and medical facts.

It's the kind of response that goes on far longer than a march.