Liu Xiaobo's Empty Chair

When the Norwegian Nobel Committee announced it was awarding the 2010 Nobel Peace Prize to the Chinese literary critic and human rights activist Liu Xiaobo, it made special note of his role in writing a remarkable political manifesto called Charter 08. In China, that same document has caused officials to throw him in jail with an 11-year sentence that is extraordinary even by Chinese standards, while taking drastic measures to silence any mention of the text.  But what is Charter 08 and why