And tens of thousands of scientists and their supporters will rally in Washington, D.C., and in other cities across the U.S. Saturday for a national “March for Science.” The rallies come as the Trump administration pursues an unprecedented campaign of science denial—on issues including climate change, vaccines and the environment. Ahead of the march, astrophysicist and science communicator Neil deGrasse Tyson released a video calling science denial a threat to democracy.

Neil deGrasse Tyson: “And so, science is a fundamental part of the country that we are. But in this, the 21st century, when it comes time to make decisions about science, it seems to me people have lost the ability to judge what is true and what is not; what is reliable, what is not reliable; what should you believe, what should you not believe. And when you have people who don’t know much about science standing in denial of it and rising to power, that is a recipe for the complete dismantling of our informed democracy.”

Democracy Now! will broadcast live from the March for Science in Washington, D.C., on Saturday, from 10 a.m. to 3 p.m. Eastern time. You can go to democracynow.org to tune in to the broadcast.