In December 2004, during Ukraine’s Orange Revolution, I spent a night in one of the many tents that had been pitched in Kiev’s central square. There were five of us inside, and it smelled like cigarettes, black tea, and sweat. Outside, it was snowing. It seemed that everyone—protesters and riot police—had a megaphone. The voices bounced off the square’s gray facades, blending with snippets of shouting, laughter, dogs barking, a couple in a nearby tent having sex. The 25-year-old travel agent who owned the tent I was staying in had taken the bus from the city of Vinnytsia, a few hours to the southwest, with some friends. The group included a medical student and a woman in her third trimester of pregnancy. “We wanted to see history happen,” the tent owner told me. The pregnant woman interjected: “But we didn’t come until we knew it was safe—until other people would be here.” In the former Soviet Union before social media, there was a calculus to demonstrating. If you wanted to demonstrate against the regime, and …