For at least the last hundred years, the world's most dynamic religion has been neither Christianity nor Islam. It is leftism. Most people do not recognize what is probably the single most important fact of modern life. One reason is that leftism is overwhelmingly secular (more than merely secular: it is inherently opposed to all traditional religions), and therefore people do not regard it as a religion. Another is that leftism so convincingly portrays itself as solely the product of reason, intellect, and science that it has not been seen as the dogma-based ideology that it is. Therefore, the vast...