Copyright 2021 NPR. To see more, visit https://www.npr.org. SACHA PFEIFFER, HOST: On July 1, Chinese leader Xi Jinping marked the one 100th anniversary of the Chinese Communist Party. He spoke before tens of thousands of people in Beijing's Tiananmen Square. This line got the biggest ovation. (SOUNBITE OF ARCHIVED RECORDING) PRESIDENT XI JINPING: (Non-English language spoken). PFEIFFER: Anybody that tries to bully, oppress or subjugate China will find themselves, quote, "on a collision course with a great wall of steel forged by over 1.4 billion Chinese people." (SOUNBITE OF ARCHIVED RECORDING) (APPLAUSE) PFEIFFER: Strong words and a strong reaction. NPR China affairs correspondent John Ruwitch takes a look at what's behind them.