The artist Ai Weiwei is the Chinese government’s worst nightmare: an internationally revered art star who uses his work and celebrity to advocate for democracy and free speech in a nation with neither. The government has employed a draconian campaign to silence him. Ai is under constant surveillance. He has been threatened, placed under house arrest and physically attacked by a police officer. Ai’s incendiary blog, read by thousands of Chinese citizens, disappeared one day. And so did he: In 2011, state police grabbed him at the airport, threw a black bag over his head and drove him to an undisclosed location, where he languished for 81 days in a tiny prison cell. Despite these attacks, Ai has continued his virulent criticism of the Chinese Communist leadership, which he deems repressive, immoral and illegitimate.