On Saturday, 800,000 Americans gathered in Washington, D.C., to participate in what they expected to be a gun control rally. What they saw was a transformative moment in American politics. March for Our Lives was, of course, a demonstration for stronger gun safety laws, fortified by delightfully specific policy proposals and replete with far-too-clever homemade signs. But it was an awakening of sorts, an introduction to the next generation of political activism.