Organizers insist the march is simply calling for “political leaders and policymakers to enact evidence-based policies in the public interest.” And yet the sentiments driving it could perhaps only have emerged in the Trump administration: A concern about valid information itself and its role in public policy, combined with deep fear about the fate of federal science budgets, which Trump has targeted for sweeping cuts.

There have, to be sure, been countless past flare-ups at the interface of science, politics, and society. And yet they’ve rarely been so mobilizing for the research world.

“The march is pretty unprecedented in terms of the scale and breadth of the scientific community that’s involved, and it does recall Physicians for Social Responsibility and various scientific groups against nuclear war in the Reagan era, that’s I think the most recent precedent,” said Robert Proctor, a professor of the history of science at Stanford University. “But this is even broader in the sense that there’s a broader perception of a massive attack on sacred notions of truth that are sacred to the scientific community.” ...