U.S. President Barack Obama has held an unprecedented question and answer session with Chinese students in Shanghai - China's commercial capital. Mr. Obama pushed the importance of freedom of information, while at the same time calling for greater cooperation between Washington and Beijing. This was the first town hall meeting by a U.S. President in China. And it amounted to a delicate balancing act for Mr. Obama. He opened the session with university students by striking a professorial tone, talking about the history of relations between Washington and Beijing, and the importance of working together to tackle global challenges. Mr....