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No great power likes to cede its No. 1 spot. One of the few times the top power ceded its position to the No. 2 power peacefully was when Great Britain allowed the United States to surge ahead in the late 19th century. Many books have been written on why this transition happened peacefully. But the basic reason seems cultural: One Anglo-Saxon power was giving way to another. Today, the situation is different. The No. 1 power is the United States, the standard-bearer of the West. The No. 2 power rapidly catching up is China, an Asian power. If China passes America in the next decade or two, it will be the first time in two centuries that a non-Western power has emerged as No. 1. (According to economic historian Angus Maddison's calculations, China was the world's No. 1 economy until...