Book excerpt: Xi Jinping has transformed China at home and abroad with a speed and aggression that few foresaw when he came to power in 2012. Finally, he is meeting resistance, both at home among disgruntled officials and disillusioned technocrats, and abroad from an emerging coalition of Western nations that seem determined to resist China's geopolitical and high-tech expansion. With the United States and China at loggerheads, Richard McGregor outlines how the world came to be split in two.